Sistema de Membrana de Ultrafiltração Cerâmica para Produção de Água Potável de Alta Qualidade

Karaelmas Fen ve Müh Derg 614149 2016 Karaelmas Fen ve Mühendislik Dergisi Journal home page httpfbdbeunedutr Research Article Corresponding Author kadirozdemir73 yahoocom Received Geliş tarihi 09022016 Accepted Kabul tarihi 11032016 A Ceramic Ultrafiltration Membrane System for Producing High Quality Drinking Water Seramik Ultrafiltrasyon Membran Sistemi İle Yüksek Kalitede İçme Suyu Üretimi Kadir Özdemir Bülent Ecevit University Department of Environmental Engineering Zonguldak Turkey Abstract In this study ultrafiltration UF with ceramic membranes was used to produce safe and quality drinking water Te small scale UF membrane system had a capacity of 144 m3d Te UF membrane filtration process includes two parts a tubular ceramic membrane formed by a porous support αalumina and a tube reactor chamber 10 m long and 5 cm in diameter to generate electrocoagulation In this study raw water treated with smallscale UF membrane systems was taken from the Alibey Lake in Istanbul City Turkey Te system removed 75 to 85 of ferrous and turbidity contaminants Te decrease in pH chloride and total hardness was similar but ammonia and manganese removal was much lower than expected Nevertheless removal of total organic carbon TOC was the best only 15 remained Te UF ceramic membrane filtration system produced water that met Turkish Standards TS266 regulated standards for drinking water in Turkey Chemical cleaning with a cleaninplace CIP operation was successful in removing fouling and scaling materials in ultrafiltration UF ceramic membrane Te UF ceramic membrane filtration system produced water with no added chemicals as a coagulant and disinfectant Indeed producing water with no chemicals and disinfection byproducts DBPs like trihalomethenes THMs is better for human health than the approaches used at conventional drinking water treatment facilities Keywords Ceramic membrane Electrocoagulation Ultrafiltration Water treatment Water quality Öz Bu çalışmada tübüler seramik membrane kullanılarak oluşturulmuş küçük ölçekli Ultafiltrasyon UF membran sistemi ile kaliteli bir içme suyu üretilmesi hedefenmiştir Bu amaçla kullanılan UF membrane filtrasyon sistemi 144 m3 günlük bir su üretim kapasitesine sahiptir Bu UF membrane filtrasyon sistemi αalumina içeren gözenekli bir destek tabakası ve elektrokoagülasyon prosesini gerçekleştirmek için 5 cm çapında ve 10 m uzunluğunda tubüler bir reactor odasından meydana gelmektedir Bu çalışmada UF membran sistemi ile arıtım amaçlı olarak kullanılacak ham su İstanbul şehrinin önemli içme suyu kaynağı olan Alibeyköy baraj gölünden sağlanmıştır Bu sistem ile yapılan deneysel çalışmalarda demir ve bulanıklık giderim oranlarının sırası ile 75 ve 85 olduğu gözlenirken pH klorür ve toplam sertlik parametre değerlerinde herhangi bir değişim olmadığı ortaya konulmuştur Bununla beraber Toplam Organik Karbon TOK değerlerinde o yaklaşık 15lik bir düşüş oldğu gözlenirken Amonyak ve Mangan değerlerinde ise tahmin edilenden daha düşük bir giderim verimi sağlandığı tespit edilmiş olup arıtma sonunda alınanan su numunelerinin bakteriyolojik olarak temiz olduğu rapor edilmiştir Bu çalışmanın en önemli sonuçlarından biri herhangi bir kimyasal ve dezenfektan kullanmadan UF membrane filtarsyon sistemi ile üretilen suyun TS266 içme suyu standartlarında yer alan temel su kalite parametre değerlerini sağlamış olmasıdır Bununla beraber konvansiyonel içme suyu arıtma tesisleri ile karşılaştırıldığında dezenfektan olarak klor kullanımı sonucu meydana gelen Trihalometanlar gibi özellikle insan sağlığı üzerinde kanserojenik etkiye sahip dezenfeksiyonyan ürünlerinin olmaması UF membrane sistemi ile üretilen içme suyunun sağlıklı güvenli ve kaliteli olduğunu ortaya koymaktadır Anahtar Kelimeler Seramik membran Elektrokoagülasyon Ultrafiltrasyon Su arıtımı Su kalitesi Özdemir A Ceramic Ultrafiltration Membrane System for Producing High Quality Drinking Water Karaelmas Fen Müh Derg 2016 614149 42 1 Introduction Te lack of safe potable water and increased demand as well as higher standards have increased the need for membrane technologies to produce high quality drinking water Bagga et al 2008 Moreover conventional water treatment processes including coagulationfocculation sedimentation fltration and disinfection processes are not very efective at meeting these stringent regulations Tus use of pressure driven membrane processes such as microfltration MF and ultrafltration UF are increasingly popular in drinking water treatment Jacangelo et al1995 Yuan and Zydney 1999 Zularisam et al2007 Furthermore the chlorine used as a disinfectant in conventional water treatment plants reacts with Natural Organic Matter NOM and produces disinfection byproducts DBPs that are carcinogenic and mutagenic Rook 1974 Membranebased fltration such as microfltration MF ultrafltration UF nanofltration NF and reverse osmosis RO have been investigated as a potential alternative to conventional water treatment options for small communities Membrane installations are easily automated Te UF NF and RO remove signifcant levels of trihalomethene THM precursors from drinking water supplies and deliver excellent microorganism control Hence membrane fltration removes turbidity reduces THM precursors and disinfects in a single step Richard and Paul 2003 Small scale membrane treatment systems such as MF and UF systems are highly efective for turbidity as well as bacteria and virus removal from surface waters such as rivers and lakes Jacangelo et al1991 Madaeni 1999 Neranga et al2014 Zhu et al2005 Tey also indirectly assist in DBPs control by lowering chemical disinfection requirements for the fltered water Furthermore the goals of smallscale treatment systems are simplicity no chemicals dynamic remote control long service interval times and low energy use Ceramic membranes have several advantages over poly meric membranes such as high chemical mechanical and thermal resistance as well as higher permeability rates than polymeric membranes Nevertheless ceramic membranes are substantially more expensive though this may be com pensated by their higher fuxes and extended lifetimes Van Der Bruggen et al2008 Kim et al2007 BarredoDamas et al2012Porous ceramic membranes are an important membrane category that is of particular interest in applica tions requiring high chemical or thermal stability Pagana et al2006 Shams Ashaghi et al2007 Tubular ceramic membranes are formed by a porous support generally a Al2O3 with one or more layers of decreasing pore diameter and an active or separating layer αalumina zirconia etc covering the internal surface of the tube Te use of ceramic membranes for microfltration and ultrafltration is of great interest because they can remediate fouling problems asso ciated with those processes and solutions ie adsorption or deposition of macromolecules on the membrane poressur face Tis strongly reduces volume fow and requires harsh chemicals and high temperatures for cleaning In turn this damages the polymeric membranes Richard et al 2013 Verberk et al 2002 Tus the use of these systems is still limited by fouling It has also been suggested that viruses are etiologic agents responsible for the majority of unidentifed outbreaks because they are typically more difcult to analyze than bacterial pathogens It is difcult to remove viruses by fltration because of their small size Tanneru and Chellam 2012 EPA 2006 Urase et al 1996 Mi et al 2005 Pontius et al 2009 Electrocoagulation EC has been widely studied in water and wastewater treatment to remove heavy metals organics bacteria hardness turbidity and other contaminants Tsouris et al 2001 Can et al 2003 Al malack et al 2004 Mills 2000 Zhu et al2005 EC has been widely studied in water and wastewater treatment Here the electrodes are consumed as the coagulant is generated and precipitated No liquid chemicals are added No basic chemical are used and the pH does not have to be adjusted Mills 2000 Zhu et al2005 Additionally EC pretreatment is an alternative to conventional chemical coagulation using Fe or Al salts prior to MF or UF membrane systems In electrocoagulation the coagulant Fe or Al is generated by electrolytic oxidation of an anode Te advantages of EC over conventional chemical coagulation include 1 no addition of lime ferric and coagulant chemicals 2 no change in bulk pH 3 simple operation and maintenance and 4 low sludge generation Bagga et al 2008 Cazinares et al 2006 Hu et al2013 Te most important advantage of EC pretreatment is the reduction in fouling problems that occurs in smallscale MF and UF membrane systems Bagga et al 2008 Al Malack et al 2004 Te aim of this study is to provide high quality potable water without added chemicals via a smallscale membrane treatment system consisting of UF ceramic membranes Özdemir A Ceramic Ultrafiltration Membrane System for Producing High Quality Drinking Water Karaelmas Fen Müh Derg 2016 614149 43 We compared the treatment performance of conventional treatment process in Kagithane Water Treatment Plant KWTP and UF membrane fltration process and characterized the pH turbidity total organic carbon TOC and total hardness 2 Materials and Method 21 Source Water Quality Water quality is an important factor in determining the treatment performance of smallscale UF membrane systems For this study raw water taken from the Alibey Lake in Istanbul City Turkey was used as feed water for smallscale UF membrane systems during the winter period January February and March in 2011 Tis surface water supply is one of the major drinking water sources of Istanbul City Also Alibey Lake is one of the most important water reservoirs in Istanbul and provides up to 700000 m3day of raw water to produce drinking water Raw water samples were collected by plant personnel as a grab sample and shipped to a water quality laboratory Istanbul Water Utilities Administration ISKI on the same day Samples were stored in the dark at 4oC to prevent biological activity prior to analysis 22 Membrane In this study the smallscale UF membrane fltration system used to purify Alibey Lake water was composed of tubular ceramic membranes formed by a porous support α Alumina Fig 1 Tese membranes consist of 580 mm long channels with an external diameter of 4 mm and 2 mm Teir efective pore sizes are 004 µm and the efective flter area is 18 m2 as surface area per volume m 2 m 3 Table 1 lists other relevant properties of these membranes 23 Electrocoagulation EC unit Coagulation process in the EC used a dedicated tube reactor Tis reactor chamber consists of a 10 m long tube 5 cm in diameter Te rodshaped iron anodes are 50 cm long Te cylindrical stainless steel cathodes are placed in a electrode chamber and are 1 m long Te total anode surface area was 100 cm2 and the current density was typically 015 mAcm2 During iron EC the following electrochemical reactions occur Anode Fe0 s Fe33e Fe3 3H2O FeOH3 s 3H Cathode 3H2O 3e 3OH 32 H2 Overall Fe03H2O FeOH3s 32 H2 24 Experimental UF Membrane Filtration Setup UF fltration experiments were conducted in a multi tubular ceramic membrane Te process was designed for a fux of 60 Lm2hr As seen in Fig 2 surface lake water was taken from the 1000 L tank with a peristaltic pump and transferred into the reactor chamber for EC processing In the meantime the iron electrodes are sacrifced at this step at a concentration of 4 ppm In this way it is possible to have dynamic inline process control as well as a short residence time in the tube reactor for foc growth After coagulation the raw water was passed into the second part including the UF ceramic membrane Te fow level and temperature sensor were located at the frst part of the reactor water levels in the reactor were held constant Permeating and backwashing operations were performed automatically with an automatic control system To save Figure 1 Tubular ceramic membrane Table 1 Typical characteristics of the membrane used in this study Parameter Value Unit Material Ceramic aAl2O3 Pore size nominal 004 µm Efective area 18 m2 Feed water fux 60 Lh1m2 Max operating pressure 065 bar Max operating temperature 30 0C pH range 411 Özdemir A Ceramic Ultrafiltration Membrane System for Producing High Quality Drinking Water Karaelmas Fen Müh Derg 2016 614149 44 pH total hardness chloride manganese and ammonia were measured according to the literature APHA 1998 3 Results 31Treatment performance of the UF ceramic membrane fltration system In this study we measured the quality of the water produced by the UF ceramic membrane fltration system Alibey Lake water was treated with the UF ceramic membrane fltration system and Table 2 details physicochemical characteristics of raw Alibey Lake water versus the treated water As seen in Table 2 the turbidity values drop from 65 NTU to below 1 NTU Te concentrations of ferrous and manganese were 003 and 005 mgL respectively in clean water In other words the removal percentage of turbidity wasapproximately 85 Te conductivity was 740 µScm1 and the pH was 771 on average in treated water Te total hardness and chloride in treated water remained relatively constant Table 2 Te drinking water was produced from Alibey Lake water with the UF ceramic membrane fltration Fig 3 illustrates energy the fltering process was planned at a low trans membrane pressure TMP Up to 025 bar of TMP was used for the expected focsizes Te membrane cleaning process used flter backwashing and chemical cleaning with an automatic control system Filter backwashing was automatically performed every 20 minutes with water treated by the UF membrane system Chemical cleaning of the membrane was automatically carried out using 200 ppm NaOCl and 500 ppm H2O2 using chemical dosage pumps every 15 hours Tis avoids membrane fouling from microbial contamination 25 Analytical Methods Te TOC analysis used high temperature combustion according to Standard Methods SM 5310 B using a Shimadzu TOCVCPH analyzer equipped with an auto sampler APHA 1998Te total iron was measured using atomic absorption spectroscopy AAnalyst 300 Perkin Elmer Corp CT after acidifying the samples to pH2 using HNO3 according to Method 3111 in the Standard Methods APHA 1998 Turbidity was determined by with a Termo turbidimeter according to Standard Methods Te Figure 2 A schematic diagram of the UF ceramic membrane fltration system Özdemir A Ceramic Ultrafiltration Membrane System for Producing High Quality Drinking Water Karaelmas Fen Müh Derg 2016 614149 45 As shown Fig 4 the pH of the water was not signifcantly infuenced by treatmentthe results were within the known target limit for Turkish Standards 266 TS266 regulated standards for drinking water in Turkey that turbidity of Alibey Lake water did not exceed 03 NTU at the efuent of the UF ceramic membrane fltration system To better compare the turbidity values we plotted the data Fig 3 tenfold Table 2 Te relevant parameters used to evaluate the UF ceramic membrane fltration system including pre and posttreatment water Parameters Units Raw Water Average Product water Average Standarts for drinking water in Turkey TSI266 pH 782 771 6585 Turbidity NTU 654 097 5 Conductivity µScm 651 664 6502000 Total Hardness mg CaCO3 L 15335 1555 300 Chloride mgL 8014 7982 250 Ammonia mgL 032 024 05 Dissolved Oxygen mgL O2 1052 111 Not defned TOC mgL 612 518 Not defned Iron mgL 011 003 02 Manganese mgL 0067 005 005 TColiBacteria cfu100 mL 20000 None None Figure 3 Turbidity values NTU in raw water and treated water with UF membrane fltration system Figure 4 pH values in raw water and treated water with a UF membrane fltration system Özdemir A Ceramic Ultrafiltration Membrane System for Producing High Quality Drinking Water Karaelmas Fen Müh Derg 2016 614149 46 generate iron in proportion to the current by operating it continuously at diferent current values Te process has been designed for a fux of 60 Lm2hr Te Fe electrodes of the system are sacrifced during the process at a concentration of 4 ppm Tis gives dynamic inline process control and a short detention time as needed for foc growth To determine the current efciency the amount of iron generated was calculated using Faradays Law Eq1 m I x t xMW ZxF Eq1 Where m is the mass in grams of Fe generated at a specifc current I amps over a time interval t seconds Term Z is the number of electrons transferred per Fe atom MW is the molecular weight 5585 g mol1 and F is Faradays constant 96486 C eq1 Te desired iron concentration was obtained by adjusting the operating current and fow rate of the source water For example when the feed fow rate was 250 mLmin and the operating current was 015 A the iron concentration was Tere was no change in total hardness during the membrane fltration as occurs with chloride treatment Fig 5a b In other words both parameters had similar removal percentages Ammonia and manganese removal through the ceramic UF membrane fltration was much lower than expectedonly 25 was removed Fig 6ab Of all of the water quality metrics turbidity had the highest removal ratio at 85 Fig 7 the TOC removal ratio was only 15 Moreover the performance of the UF membrane system was much lower for the TOC parameter Fig 8 Tis result is expected because the electrocoagulation time is very short Tis also means that it is not enough time for the needed focgrowth in the EC due to low retention time No bacteria were found in the UFfltered water despite the lack of chlorine Tus no disinfection byproducts were present in the UF water that might result in adverse health efects 32 Operation of the EC unit After designing the EC unit it was tested for its ability to Figure 5 A Total hardness mg CaCO3L and B Chloride mgL values in raw water and treated water from the UF membrane fltration system Figure 6 A Ammonia mgL and B manganese mgL in raw water and treated water A A B B Özdemir A Ceramic Ultrafiltration Membrane System for Producing High Quality Drinking Water Karaelmas Fen Müh Derg 2016 614149 47 and 20 minutes After 5 cycles of operation the system was automatically backwashed for 2 minutes As shown in Fig 10 when the TMP was 065 bar the system automatically switches to chemical cleaning mode to remove bacteria and or viruses from the membrane Chemical cleaning with cleaninplace CIP operation is the usual method to restore the membrane permeability Tere are several reagents including alkalis acids oxidants chelating agents and surfactants that could be used for CIP Zhu et al2005 Jacb and Jafrin 2000 Many aspects should be considered when selecting CIP reagents Te two main factors are feed composition and the composition of the fouling layer Zhu et al2005 In this study H2O2 and 36 mgL Fig 9 presents FeIII concentration as well as the EC unit operating current Te Fe III formation at 250 mLmin is a function of EC operating current 33Efects of backwashing and chemical cleaning on the UF ceramic membrane fltration Te backwashing and chemical cleaning processes were conducted automatically in the UF membrane system to control membrane fouling Ceramic membranes have a higher permeability versus traditional polymeric membranes if the backwash interval is extended Zhu et al 2005 Jegatheesen et al 2009 In this study the UF ceramic membrane fltration was operated with Alibeyköy Lake water for 24 hours One cycle required between 15 Figure 7 Total iron values mgL in raw water and treated water Figure 8 TOC mgL values in raw water and treated water treated Özdemir A Ceramic Ultrafiltration Membrane System for Producing High Quality Drinking Water Karaelmas Fen Müh Derg 2016 614149 48 fltration Te TMP during backwash never exceeded 035 Bar Te TMP after every backwash at the start of the fltration cycle varied between 017 and 019 bar 4 Conclusion In this study we produced potable water in accordance with EC standards using UF ceramic membrane fltration system with no added chemicals We studied the performance metrics of the UF membrane Except for the TOC and ammonia all of the relevant water parameters including pH turbidity Fe and manganese met the required specifcations Moreover the Fe and turbidity were removed at nearly 75 and 85 respectively Bacteria were not found in the treated water despite the lack of chlorine During EC the Fe electrodes are consumed at concentration of 4 ppm Moreover the Fe III formed at 250 mLmin is a function of the EC unit operating NaOCl were selected because they have strong chemical inertia and do not afect the thermal stability of the ceramic membrane Te use of chemicals was limited to cleaning and the total amount needed can be extrapolated from the volume of the flter elements During this experiment the chemical concentration was adjusted to pH 2 and 500 ppm H2O2 and 200 ppm NaOCl Under normal circumstances we used 15 minutes of soaking Figure 10 shows changes to the TMP as a function of time 0432 hours during operation As shown the Figure 10 the TMP increases after chemical cleaning Te TMP decreased from 065 to 01 bar It also demonstrated that a large number of microorganisms and colloids resulting from membrane fouling were removed by chemical cleaning Fig 10 Furthermore TMP during the fltration tests varied between 017 Bar and 023 Bar Te fow was kept constant during Figure 9 Fe III generated at 250 mLminute as a function of EC operating current Figure 10 TMP changes as a function of time during UF ceramic membrane fltration Özdemir A Ceramic Ultrafiltration Membrane System for Producing High Quality Drinking Water Karaelmas Fen Müh Derg 2016 614149 49 Kim HG Park C Yang J Lee B Kim SS Kim S 2007 Optimization of backfushing conditions for ceramic ultrafltration membrane of disperse dye solutions Desalination 202 150155 Madaeni SS 2009 Te application of membrane technology for water disinfection Water Res 33 2 301308 Mi B Marinas BJ Curl J Sethi S Crozes G Hugaboom D 2005 Microbial passage in low pressure membrane Elements with Compromised Integrity Environ Sci Technol 39 11 42704279 Mills DA 2000 New process for electrocoagulation J Am Water Works Assoc 92 6 3443 Neranga P Chellam S Chellam G 2014 Mechanisms of Physically Irreversible Fouling during Surface Water Microfltration and Mitigation by Aluminum Electrofotation Pretreatment Environ Sci Technol 48 11481157 Pagana A Stoitsas K Zaspalis VT 2006 Applied pilotscale studies on ceramic membrane processes for the treatment of waste water streams Global Nest J 8 2330 Pontius FW Amy GL Hernandez MT 2009 Fluorescent microspheres as virion surrogates in lowpressure membrane studies J Membrane Sci 335 12 4350 Porcelli N Judd S 2010 Chemical cleaning of potable water membranes a review Sep Purif Technol 71 137143 Richard JC Paul KTL 2003 Ceramic Membranes for Environmental Related Applications Fluid Particle Sep J 151 5160 Rook JJ 1974 Formation of haloforms during chlorination of natural waters Water Treat Exam 23 234243 Shams Ashaghi K Ebrahimi M Czermak P 2007 Ceramic Ultra and Nanofltration Membranes for Oilfeld Produced Water Treatment Te open Environ J 1 18 Tanneru CT Chellam S 2012 Mechanisms of virus control during iron electrocoagulation Microfltration of surface water Water Res 46 21112120 Tsouris C Depaoli DW Shor JT Hu M Ying TY 2001 Electrocoagulation for magnetic seeding of colloidal particles Colloids Surf A Physicochem Eng Aspects 1773 223233 Van der Bruggen B Mänttär M Nyström İM 2008 Drawbacks of applying nanofltration and how to avoid them A review Sep Purif Technol 63251263 Verberk JQ JC Hoogeveen PE Futselaar H Dijk JCV 2002 Hydraulic distribution of water and air over a membrane module using AirFlush Water Science and Technology Water Supp 2 297304 Yuan W Zydney AL 1999 Humic acid fouling during microfltration J Membrane Sci 1571 112 Zhu B Cliford AD Chellam S 2005 Comparison of electrocoagulation and chemical coagulation pretreatment for enhanced virus removal using microfltration membranes Water Res 39 30983108 Zularisam AW Ismail AF Salim MR Sakinah M Ozaki H 2007 Te efects of natural organic matter NOM fractions on fouling characteristics and fux recovery of ultrafltration membranes Desalination 21213 191208 current Te backwashing and chemical cleaning processes were conducted automatically by UF membrane system to control membrane fouling After chemical cleaning the TMP decreased from 065 to 01 bar In summary the UF ceramic membrane fltration system produced drinking water that met TS266 standards with no added chemicals for coagulation and disinfection Producing water without DBPs like THM ofers better safety and quality for humans than water produced by conventional treatment systems 5 References Almalack MH Bukhar AAİ Abuzaid NS 2004 Crossfow microfltration of electrocoagulated kaolin suspension fouling mechanism J Membrane Sci 243 143 American Public Health Association APHA 1998 Standard Methods for the Examination of Water and Wastewater 20th ed Washington DC USA Bagga A Chellam S Cliford DA 2008 Evaluation of iron chemical coagulation and electrocoagulation pretreatment for surface water microfltration J Membrane Sci 309 8293 BarredoDamas S AlcainaMiranda MI IborraClar MI MendozaRoca JA 2012 Application of tubular ceramic ultrafltration membranes for the treatment of integrated textile wastewaters Chemical Engineering Journal 192 211 218 Can OT Bayramoglu M Kobya M 2003 Decolorization of reactive dye solutions by electrocoagulation using aluminum electrodes Ind Eng Chem Res 42 14 33913396 Caˇnizares FP Martınez C Jimenez J Lobato RMA 2006 Coagulation and electrocoagulation of wastes polluted with dyes Environ Sci Technol 40 6418 Environmental Protection Agency EPA 2006 National Primary Drinking Water Regulations Ground Water Rule Final Rule Federal Register 40 CFR Parts 9 141 and 142 71 6557465660 Hu CY Lo SL Kuan WH 2013 Efects of coexisting anions on fuoride removal in electrocoagulation EC process using aluminum electrodes Water Res 37 4513 Jacangelo JG Adham SS Laˆıne JM 1995 Mechanism of Cryptosporidium Giardia and MS2 virus removal by MF and UF J Am Water Works Assoc 87 107 Jacangelo JG Laine JM Carns KE Cummings EW Mallevialle J 1991 Lowpressure membrane fltration for removing Giardia and microbial indicators J Am Water Works Assoc 83 9 97106 Jacob S Jafrin MY 2000 Purifcation of brown cane sugar solutions by ultrafltration with ceramic membranes investigation Separ Sci Technol 35 9891010 Jegatheesan V Phong DD Shu L Ben Aim R 2009 Performance of ceramic micro and ultrafltration membranes treating limed and partially clarifed sugar cane Juice J Membrane Sci 327 6977 Citation Kook H Park C Engineered Approaches to Facile Identification of Tiny Microplastics in Polymeric and Ceramic Membrane Filtrations for Wastewater Treatment Membranes 2022 12 565 httpsdoiorg103390 membranes12060565 Academic Editor Pei Sean Goh Received 6 May 2022 Accepted 27 May 2022 Published 28 May 2022 Publishers Note MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil iations Copyright 2022 by the authors Licensee MDPI Basel Switzerland This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution CC BY license https creativecommonsorglicensesby 40 membranes Article Engineered Approaches to Facile Identification of Tiny Microplastics in Polymeric and Ceramic Membrane Filtrations for Wastewater Treatment Heejin Kook and Chanhyuk Park Department of Environmental Science and Engineering Ewha Womans University Seoul 03760 Korea 202eng13ewhainnet Correspondence chpewhaackr Abstract Wastewater treatment plants WWTPs contribute to the release of significant quantities of microplastics into the aquatic environment The facile identification of microplastics and an under standing of their occurrence and transport through WWTPs are essential for improving microplastic retention Potential microplastic treatment technologies for both polymeric and ceramic membrane filtrations were systematically investigated to inform decisions on the optimal choice of membrane for effective microplastic retention A blocking filtration model based on a simple linear regression fitting was used in experiments on the filtration of microplastic suspensions to determine the relative importance of individual fouling mechanisms Unlike the commonly applied spectroscopic tech niques the facile identification approaches that are closely related to the amounts of particles within wastewater samples attempted to identify tiny microplastics 10 µm by comparing them against silica particles for reference A larger decline in the normalized permeate flux was observed for 01 µm polystyrene microplastics while standard pore blocking appeared to be the dominant fouling mechanism for all membranes More microplastics based on turbidity and total solids were removed using the ceramic membrane than the other polymeric membranes However fewer microplastics based on the particle size distribution analysis were removed using the ceramic membrane as the pore size measurements gave a relatively large pore size for the ceramic membrane compared with other polymeric membranes even though a nominal pore size of 01 µm for all membranes were provided by the suppliers The contribution of microplasticcontaining synthetic wastewaters to overall flux decline was significantly greater than those of identical microplastic suspensions because of the aggregation of larger microplastics with dissolved organic matter in synthetic wastewater leading to the formation of a cake layer on the membrane surface Despite the challenges associated with the facile identification approaches our findings provided deeper insights and understanding of how microplastics behave in membrane filtration which could enable the application of potential microplastic treatment technologies Keywords ceramic membrane tiny microplastics particle size distribution analysis polymeric membrane wastewater 1 Introduction Microplastics are generally defined as small plastic pieces less than 5 mm in length that can be harmful to aquatic life 12 Primary microplastics are used in many personal care and cosmetic products while secondary microplastics can be formed from a variety of sources including larger plastic debris that degrades into progressively smaller pieces Microbeads contained within facial cleansers and toothpaste along with the thousands of microplastic fibers dislodged during washing are often directly discharged into wastewa ter 34 However microplastics entering wastewater treatment plants WWTPs can be partially treated before being released into the aquatic environment depending on the treat ment processes employed 57 The reported types and concentrations of microplastics in Membranes 2022 12 565 httpsdoiorg103390membranes12060565 httpswwwmdpicomjournalmembranes Membranes 2022 12 565 2 of 17 influent wastewater samples varied greatly in different WWTPs The most common types of microplastics detected at WWTPs are polyester PES 2889 polyethylene PE 451 polyethylene terephthalate PET 435 and polyamides PA 330 along with other polymers such as acrylate polypropylene PP and polystyrene PS 527 8 These microplastics can be treated via a series of wastewater treatment processes typically com posed of primary clarifiers biological treatments and final sedimentation At present few existing studies on microplastic removal in WWTPs compare removal efficiency during preliminary primary secondary and tertiary treatments 59 Existing studies have shown that a significant proportion of microplastics are removed by preliminary and primary treat ments pretreatment with the removal efficiency dependent on properties such as the size distribution shape and density of the microplastics 61011 Secondary treatments can further decrease microplastic concentrations in wastewater and can effectively remove more fragment particles than fibers while tertiary treatments may provide substantial additional polishing of microplastics before release depending on the treatment process 61112 A significant proportion of microplastics 20 µm are effectively removed in advanced finalstage wastewater treatment Membranerelated technologies demonstrate the highest removal efficiency 999 followed by rapid sand filters RSFs and dissolved air flotation DAF with a removal efficiency of 97 and 95 respectively 9 When using membranes with a nominal pore size of 04 µm microplastics concentrations decreased from 69 10 to 0005 0004 particlesL 5 Recent studies have also shown that the relative abun dance of microplastics decreased when membrane bioreactor MBR processes are used in wastewater treatment 1315 Emerging applications involving alternative membrane materials such as ceramic membranes have been increasing in recent years as they offer greater permeate flux and lower fouling propensity to a variety of wastewater treatments through their membranebased processes 1619 Microplastic analysis can be classified into physical and chemical characterizations 5 Chemical characterizations are mainly used to determine the composition of microplastics and can increase the accuracy of microplastic identification and further explore their com position Current chemical analysis methods include destructive techniques such as gas chromatography coupled to mass spectrometry GCMS which includes pyrolysisGCMS and thermal extraction desorptionGCMS 2024 and nondestructive spectroscopic tech niques such as Fourier transform infrared FTIR 2527 and Raman spectroscopy 2829 Among these techniques spectroscopic approaches are most commonly used to identify microplastics contained in environmental samples although equipment limitations make it difficult to detect tiny microplastics 1 µm 3031 FTIR is the most frequently reported method used in the analysis of microplastics found in WWTPs However traditional FTIR analysis is very laborintensive as the microplastics first need to be identified under light microscope and then the spectrum of each particle needs to be individually analyzed The recent development of focal plane array FPA based microFTIR imaging may be more effective in evaluating the spectra of individual particles in a wastewater sample result ing in highthroughput analysis of the total microplastic contents 2632 However the microFTIR technique is still limited to specific diffraction ranges eg 10 µm at 1000 cm1 and samples of 1020 µm in size can rarely be analyzed 2 Compared with FTIR Raman techniques can give a better spatial resolution down to 1 µm 3334 However care must be taken when purifying the samples in order to avoid accidental sample modification prior to analysis 35 Unlike chemical characterization methods physical characterization mainly refers to characterizing the size distribution of microplastics as well as assessing other physical parameters 36 The technique can be used to rapidly measure the mor phology of smallsized microplastics using relatively inexpensive equipment Additionally as it requires no pretreatment it is less laborintensive Although the method cannot determine specific polymer types and cannot eliminate potential errors the facile and indirect quantification approaches for identifying the microplastics such as turbidity mass and size distribution may be able to highlight the importance of determining microplastic transport through WWTPs Therefore several water quality parameters that are used to Membranes 2022 12 565 3 of 17 assess the quality of wastewater discharged into the environment were suggested for use in characterizing the properties of microplastic particles in wastewater samples 3739 The present study addresses the potential of several engineered facile and indirect identification approaches by examining the removal efficiency and behavior of microplastics during wastewater treatment using membrane processes Two tiny differently sized PS and PE 01 and 10 µm microplastics that cannot be measured by other spectroscopic techniques were chosen as the target microplastics based on their high levels of prevalence in WWTPs and their transport mechanisms were compared with standard silica particles By applying several facile microplastic identification methods the study aimed to fulfil the following specific objectives i to investigate the effects of different types of particles silica particle and microplastic ii the effects of different sizes of microplastics iii the effects of different types of microplastics PS and PE and iv the effects of synthetic wastewater samples on filtration and treatment behaviors The results are expected to offer valuable insights into how we operate a membrane treatment system to improve the retention of microplastics by better understanding the transport of these relatively tiny microplastics 2 Materials and Methods 21 Silica Particle and Microplastic Nonfunctionalized silica microsphere particle with natural hydroxyl or silanol groups was purchased from EPRUI Biotech Co Ltd Shanghai China as a reference particle The silica microspheres of 01 µm nominal diameters were supplied in 10 solids ww aqueous suspensions Monodispersed PS microplastics of two different sizes 01 and 10 µm at 2 solids ww aqueous suspensions SigmaAldrich St Louis MO USA were used since they are a particle size standard and are ideal for characterizing the particle size distribution of the samples PE microplastics with 10 µm Cospheric LLC Santa Barbara CA USA in dry powder form were suspended in an aqueous solution with a surfactant Tween 80 Cospheric LLC Santa Barbara CA USA of 05 mgL prior to being suspended in deionized DI water DirectQ 3 Water Purification System Millipore Corp Billerica MA USA since PE microplastics are hydrophobic The concentrations of silica particles and microplastics were suspended in DI water at 50 mgL for all experiments For the wastewater samples the same concentrations of each PS and PE microplastics were added to the prepared synthetic wastewater samples that were adapted from previous studies to maintain the consistency of wastewater composition 40 22 Membrane Filtration Experiments Two polyvinylidene fluoride PVDF membranes Synder Sterlitech Corp Kent WA USA and SteriLUX Meissner Filtration Products Camarillo CA USA and the Anopore inorganic membrane Anodisc Whatman Inc Maidstone UK with a 131 cm2 effective surface area were employed in a benchscale membrane filtration system 4142 The Anopore inorganic membrane is composed of a highpurity alumina matrix which is manufactured electrochemically and is hydrophilic so as to be compatible with most solvents All membranes were peripherally bonded to an annular polypropylene ring except for the 13 mm diameter disc for ease of handling and were suitable for both vacuum and pressure filtration Pore sizes and the materials for the top layer provided by the membrane suppliers are shown in Table 1 Table 1 Specifications of polymeric and ceramic membranes for the filtration experiments Type Material Supplier Pore Size µm 1 Pore Size nm 2 Roughness nm Pure Water Permeability L m2 h1 bar1 Porosity Polymeric PVDF Synder 01 273 1185 9925 756 PVDF SteriLUX 01 456 378 16209 316 Ceramic Al2O3 Anodisc 01 737 289 24398 951 1 provided by supplier 2 computed by Equation 1 Membranes 2022 12 565 4 of 17 The pore sizes given by the membrane suppliers were similar to each other However the actual membrane pore sizes were determined by measuring the retention of polyethy lene oxides PEO SigmaAldrich St Louis MO USA with several different molecular weights ranging from 100 kDa to 5000 kDa The molecular weight cutoff MWCO of the membranes refers to the minimal molecular weight of organic solutes ie PEO in this study where 90 of the solute can be retained 18 The membranes were filtered with 3 gL PEO solutions at 10 bar for 30 min using a peristaltic pump GT150D Green Tech Co Ltd Gumisi Korea and PEO retention was determined by measuring the non purgeable organic carbon NPOC concentration in the feed and the permeate using a total organic carbon TOC analyzer TOCLCPH Shimadzu Corp Kyoto Japan 4142 The MWCOs in Daltons were converted to metric size nm using the EinsteinStokes diameter equation for PEO according to the Equation 1 43 Rs nm 001044 Mw0587 1 where Rs is the Stokes radius nm and Mw is the MWCO Da Atomic force microscopy AFM HRAFM AFM Workshop Corp Hilton Head Island SC USA was used to measure the surface roughness of the membranes in noncontact mode with a 10 µm 10 µm scale The porosity was measured using an AutoPore IV 9500 mercury poremeter Micromeritics Instrument Corp Norcross GA USA based on the intrusion of mercury into a porous membrane structure under stringently controlled pres sures For these measurements the membranes were cut into small pieces approximately 10 mm in length The membrane filtration experiments were performed with identical silica particles and microplasticcontaining aqueous solutions A peristaltic pump provided an accurate constant feed flow during all the experiments at a constant transmembrane pressure TMP of 10 bar which was maintained by a pressure gauge in front of the membrane The permeate samples were collected in a glass beaker that was constantly being weighed using an automated electronic scale GX4000 AD Co Ltd Tokyo Japan with the weight of the changing volume indicating flux changes Throughout the experiment 2 L of feed was stirred at 100 rpm using a magnetic stirrer MSH20A DAIHAN Scientific Co Ltd Wonju Korea All the experiments were carried out in duplicate Firstly the samples were filtered with DI water to remove contaminants from the system then the feed water was replaced with ordinary water for the test The subsequent filtration experiment lasted approximately 25 h and all experiments were performed at room temperature 208 06 C 23 Analytical Methods Samples for analysis were collected regularly from the feed and permeate in the benchscale membrane filtration unit Several physicochemical parameters related to particle concentration were measured in the aqueous solutions The feed and permeate concentrations were used to calculate the retention which represents the amounts of particles retained by the membranes Turbidity was measured using a portable turbidimeter 2100Q Hach Company Loveland CO USA The TS were measured by weighing the amounts of solids present in a known volume of sample in accordance with the Standard Methods 2540 DE APHA et al 1992 The method involved weighing a beaker filling it with a known volume evaporating the water in an oven and completely drying the residue and then weighing the beaker with the residue The TS concentration was equal to the difference between the weight of the beaker with the residue and the weight of the beaker without it The size distribution of the particles was measured using a Mastersizer 3000 Malvern Panalytical Ltd Malvern UK 24 Fouling Mechanisms Blocking filtration models describe the four mechanisms of membrane fouling by colloidal particles Figure S1 in Supplementary Material as a complete pore blocking b standard pore blocking c intermediate pore blocking and d cake filtration 4445 Complete pore blocking occurs when a particle reaching the membrane blocks a pore entrance without superimposing over other particles when the particle sizes are similar to the nominal pore size of the membrane Standard pore blocking occurs when particles are deposited within the pores resulting in a decrease in the pore volume Intermediate pore blocking indicates that some particles deposit on other particles while other particles block membrane pores as represented by complete pore blocking Cake filtration allows the accumulation of deposited particles on the membrane surface since the membrane pores are already covered by other particles 46 For membrane filtration carried out in a constant TMP mode with spherically shaped foulants that are completely retained the equations describing the relationship between the total filtered volume V and filtration time t for the individual fouling mechanisms are shown below 44 Kb V Q0 1 eKb t Complete pore blocking 2 Ks t 2 t V 1 Q0 Standard pore blocking 3 Ki V ln1 Ki Q0 t Intermediate pore blocking 4 Kc V 2t V 2 Q0 Cake filtration 5 where Q0 is the initial flow rate and K is the constant with the subscript indicating the blocking mechanism An alternative approach to identifying colloidal fouling mechanisms involves applying the blocking filtration models in their integrated forms which involves a straightforward linear leastsquare fit and allows for facile identification of individual fouling mechanisms Clear identification and differentiation between the pore blocking mechanisms has important practical implications as knowing the fouling mechanism can determine the optimal choice of membrane In this study we performed deadend filtration experiments using polymeric and ceramic membranes for retaining tiny microplastics before fitting Equations 25 to the experimental flux data using linear leastsquare fitting to identify the relative importance of individual fouling mechanisms 3 Results and Discussion 31 Effect of Different Types of Particles on the Filtration and Treatment Performance We investigated the effects of two different types of particles silica particles and PS microplastics with the same average size 01 μm on filtration and treatment performance to further understand microplastic transport compared with spherical silica particles used for reference Figure 1 shows a comparison of the filtration behavior of silica particles and PS microplastics for two different polymeric membranes Synder and SteriLUX and a ceramic membrane Anodisc with the same nominal membrane pore size of 01 μm The normalized permeate flux decline of PS microplastics was slightly greater than that of the silica particles for three different membrane filtrations which could be explained by the steric size mechanism that predominates in microfiltration MF membranes The distribution of particle sizes and membrane pores were thus investigated to obtain a better understanding of filtration and treatment behavior The particle size distribution of the silica particles and the 01 μmsized PS microplastics provided by the manufacturer is shown in Figure S2 in Supplementary Material The results are displayed as a cumulative frequency distribution graph showing the different peak populations of particles obtained by measuring the intensity of light scattered by a laser beam passing through a dispersed particulate sample using laser diffraction techniques The results have also been presented as diameter D values which describe the percentage of particles that are smaller than or equal to the percentage cutoff The PS microplastics exhibited the narrowest particle size distribution ranging from 00103 μm while the silica particles had a Membranes 2022 12 565 6 of 17 broader distribution of sizes ranging from 00108 µm For example the median size value D50 0063 00005 µm in PS microplastics was smaller than 10 of the cumulative mass of silica particles D10 0079 00002 µm while the D90 value of silica particles was twice as large as that of the PS microplastics The estimation of the relatively accurate membrane pore sizes for three different membranes which had a pore size of 01 µm suggested by the manufacturer was performed with PEO solutions and achieved a 90 retention Figure 2 shows the cumulative lognormal distribution function Their retention results showed a PEO retention greater than 901 for PEO solutions of 5806 kgmol Synder PEO solutions of 14561 kgmol SteriLUX and PEO solutions of 36527 kgmol Anodisc The computed nominal pore sizes for the membranes were empirically estimated to be 273 456 and 737 nm according to Equation 1 Membranes 2022 12 x FOR PEER REVIEW 6 of 17 SteriLUX and a ceramic membrane Anodisc with the same nominal membrane pore size of 01 μm The normalized permeate flux decline of PS microplastics was slightly greater than that of the silica particles for three different membrane filtrations which could be explained by the steric size mechanism that predominates in microfiltration MF membranes The distribution of particle sizes and membrane pores were thus investigated to obtain a better understanding of filtration and treatment behavior The particle size distribution of the silica particles and the 01 μmsized PS microplastics provided by the manufacturer is shown in Figure S2 in Supplementary Material The results are displayed as a cumulative frequency distribution graph showing the different peak populations of particles obtained by measuring the intensity of light scattered by a laser beam passing through a dispersed particulate sample using laser diffraction techniques The results have also been presented as diameter D values which describe the percentage of particles that are smaller than or equal to the percentage cutoff The PS microplastics exhibited the narrowest particle size distribution ranging from 00103 μm while the silica particles had a broader distribution of sizes ranging from 00108 μm For example the median size value D50 0063 00005 μm in PS microplastics was smaller than 10 of the cumulative mass of silica particles D10 0079 00002 μm while the D90 value of silica particles was twice as large as that of the PS microplastics The estimation of the relatively accurate membrane pore sizes for three different membranes which had a pore size of 01 μm suggested by the manufacturer was performed with PEO solutions and achieved a 90 retention Figure 2 shows the cumulative lognormal distribution function Their retention results showed a PEO retention greater than 901 for PEO solutions of 5806 kgmol Synder PEO solutions of 14561 kgmol SteriLUX and PEO solutions of 36527 kgmol Anodisc The computed nominal pore sizes for the membranes were empirically estimated to be 273 456 and 737 nm according to Equation 1 Figure 1 Normalized water flux decline of silica and PS microplastic particles with an average size of 01 μm for a Synder b SteriLUX and c Anodisc membranes Figure 1 Normalized water flux decline of silica and PS microplastic particles with an average size of 01 µm for a Synder b SteriLUX and c Anodisc membranes Membranes 2022 12 x FOR PEER REVIEW 7 of 17 Figure 2 Cumulative distribution function for polyethylene oxide PEO solutions with a molecular weight MW of 1005000 kgmol kDa with the polymeric Synder and SteriLUX and ceramic Anodisc membranes and with an average pore size of 01 μm Retention performance is based on measured total organic carbon TOC concentrations of the solutes Taken together these observations suggest that the normalized permeate flux decline in PS microplastics was slightly greater than the silica particles because the distributions and diameter values were composed of particles with a small size range which could lead to pore blocking Furthermore smaller membrane pores caused less flux decline for both particles although the differences were minimal because the particles could easily penetrate through or accumulate on the membranes with larger pore sizes because of relatively lower membrane resistance The cake filtration would be expected to be the predominant fouling mechanism because the D90 values of both silica particles and PS microplastics are larger than the estimated average pore sizes of the three different membranes However the results of the best fit by the blocking filtration models shown in Equations 25 with individual R2 values indicated that a variety of fouling behaviors such as complete standard intermediate pore blocking and cake filtration were observed because the D10 values of the silica particles and PS microplastics are similar to the Synder and Anodisc membrane pores respectively Table 2 For the PS microplastics standard pore blocking was the dominant fouling mechanism because the relatively smaller particles could easily be deposited into the internal pore walls of the membranes while the silica particles demonstrated various fouling mechanisms due to their wider range of particle sizes The main fouling mechanisms were not significantly altered regardless of the membrane pores suggesting that these fouling mechanisms were mainly determined by particle sizes Table 2 R2 values corresponding to the fouling mechanisms estimated by the blocking filtration model for silica particles and PS microplastics during the three different membrane filtrations Particle Membrane Complete Pore Blocking Standard Pore Blocking Intermediate Pore Blocking Cake Filtration Silica Synder 09722 09972 09884 09954 SteriLUX 09256 09979 09549 09733 Anodisc 08303 09527 09560 09887 PS microplastic Synder 06525 09825 07778 08836 SteriLUX 07583 09997 08946 08908 Anodisc 07813 09525 07735 06617 Effluent guidelines for these particles are mandatory for wastewater discharged from domestic wastewater treatment facilities based on the performance of treatment Figure 2 Cumulative distribution function for polyethylene oxide PEO solutions with a molecular weight MW of 1005000 kgmol kDa with the polymeric Synder and SteriLUX and ceramic Anodisc membranes and with an average pore size of 01 µm Retention performance is based on measured total organic carbon TOC concentrations of the solutes Taken together these observations suggest that the normalized permeate flux decline in PS microplastics was slightly greater than the silica particles because the distributions and diameter values were composed of particles with a small size range which could lead to pore blocking Furthermore smaller membrane pores caused less flux decline for both particles although the differences were minimal because the particles could easily penetrate through or accumulate on the membranes with larger pore sizes because of relatively Membranes 2022 12 565 7 of 17 lower membrane resistance The cake filtration would be expected to be the predominant fouling mechanism because the D90 values of both silica particles and PS microplastics are larger than the estimated average pore sizes of the three different membranes However the results of the best fit by the blocking filtration models shown in Equations 25 with individual R2 values indicated that a variety of fouling behaviors such as complete standard intermediate pore blocking and cake filtration were observed because the D10 values of the silica particles and PS microplastics are similar to the Synder and Anodisc membrane pores respectively Table 2 For the PS microplastics standard pore blocking was the dominant fouling mechanism because the relatively smaller particles could easily be deposited into the internal pore walls of the membranes while the silica particles demonstrated various fouling mechanisms due to their wider range of particle sizes The main fouling mechanisms were not significantly altered regardless of the membrane pores suggesting that these fouling mechanisms were mainly determined by particle sizes Table 2 R2 values corresponding to the fouling mechanisms estimated by the blocking filtration model for silica particles and PS microplastics during the three different membrane filtrations Particle Membrane Complete Pore Blocking Standard Pore Blocking Intermediate Pore Blocking Cake Filtration Silica Synder 09722 09972 09884 09954 SteriLUX 09256 09979 09549 09733 Anodisc 08303 09527 09560 09887 PS microplastic Synder 06525 09825 07778 08836 SteriLUX 07583 09997 08946 08908 Anodisc 07813 09525 07735 06617 Effluent guidelines for these particles are mandatory for wastewater discharged from domestic wastewater treatment facilities based on the performance of treatment technolo gies We tried to determine whether some of the effluent guidelines could be used as an indirect measurement by evaluating any correlations with microplastics based on the relatively facile and rapid measurements of water quality parameters in engineered systems such as turbidity TS and particle size distribution For example linear correla tions were observed between increasing feed concentration and higher values of turbidity and TS for silica particles and PS microplastics The turbidity values of feed water were 291 01 NTU for silica particles and 1053 05 NTU for PS microplastic despite being prepared with the same concentrations in an aqueous solution at neutral pH while TS concentrations had similar values The changes in turbidity and TS concentrations during the three different membrane filtrations were evaluated as retention performance resulting in removal of over 90 for all membranes Figure S3 in Supplementary Material The turbidity retention for silica particles increased as membrane pore size decreased while there were no significant changes in PS microplastic retention However turbidity which is a qualitative characteristic that imparted by particles obstructing the transmittance of light through a water sample has no legal bearing on wastewater effluent from treatment plants transport of particles can be analyzed in more detail using the results of TS concentration changes TS measurements can be useful as an indicator of the total weight of particles in wastewater samples As with turbidity concentrations are closely related to particle amounts and regular monitoring of TS can help detect trends that might indicate the quantity of microplastics in wastewater samples Any changes in TS measured during the filtration test with the membranes indicated that TS retention for silica particles and PS microplastics increased as membrane pore size increased However there are limitations to quantifying microplastic amounts because their total weight is difficult to distinguish from other solids suspended in water Particle size distribution analysis which can determine and report information about the size and range of particles representative of a given material could be one of the facile and indirect measurement indicators with which to gain insight into the transport mechanisms in membrane filtrations This approach would not be able to directly evaluate Membranes 2022 12 565 8 of 17 particle removal but could evaluate specific distributions of particles both before and after membrane filtration suggesting that the retention mechanism of particles could be determined by understanding the interactions between particle size and membrane pore The results of the particle size distribution analysis in feed and permeate water samples that contained silica and PS microplastic with the same concentrations are shown in Figure 3 The D10 and D50 values of silica and PS microplastics for all membranes decreased significantly after membrane filtration However the D90 values in the permeate water samples were analyzed at 0170002285 µm for silica particles even though the membrane pores were estimated at 0027300737 µm This seems to indicate that slightly larger particles can penetrate the membrane pores due to the substantial pore size distribution of the membranes This phenomenon was consistent with the results for the PS microplastic meaning that size distribution analysis might be useful for understanding the behaviors of microplastics in membranebased treatment processes Membranes 2022 12 x FOR PEER REVIEW 9 of 17 Figure 3 Particle size distributions in feed and permeate water samples after membrane filtration for a silica particles and b PS microplastics with an average size of 01 μm 32 Effect of Different Sizes of PS Microplastics on Filtration and Treatment Performance We investigated the effects of two different sizes 01 and 10 μm of PS microplastics on filtration and treatment performance to understand their filtration and fouling mechanisms with polymeric and ceramic membranes Figure 4 presents the filtration behaviors of the two different sized PS microplastics for the Synder SteriLUX and Anodisc membranes with the same average pore size of 01 μm as provided by the respective manufacturers A relatively rapid flux decline was observed for small PS microplastics with 01 μm with the normalized permeate flux suddenly decreasing after a few minutes and then consistently maintained for all membranes These observations were attributed to standard or complete pore blocking because the 01 μm PS microplastic is close to the average membrane pore size of 01 μm Through blocking filtration model analysis small PS microplastics satisfy the standard pore blocking because they can penetrate and attach to the inner wall within the membrane pores leading to severe membrane fouling Table 3 For the 10 μm PS microplastics the normalized permeate flux at the Synder membrane which had the smallest estimated membrane pore size did not decrease as much as the SteriLUX and Anodisc membranes meaning that small membrane pores might be advantageous in mitigating fouling Figure 4 Normalized water flux decline of 01 and 10 μm PS microplastics for a Synder b SteriLUX and c Anodisc membranes Table 3 R2 values corresponding to the fouling mechanisms estimated by the blocking model for 01 and 10 μm PS microplastics during the three different membrane filtrations Figure 3 Particle size distributions in feed and permeate water samples after membrane filtration for a silica particles and b PS microplastics with an average size of 01 µm 32 Effect of Different Sizes of PS Microplastics on Filtration and Treatment Performance We investigated the effects of two different sizes 01 and 10 µm of PS microplastics on filtration and treatment performance to understand their filtration and fouling mechanisms with polymeric and ceramic membranes Figure 4 presents the filtration behaviors of the two different sized PS microplastics for the Synder SteriLUX and Anodisc membranes with the same average pore size of 01 µm as provided by the respective manufacturers A relatively rapid flux decline was observed for small PS microplastics with 01 µm with the normalized permeate flux suddenly decreasing after a few minutes and then consistently maintained for all membranes These observations were attributed to standard or complete pore blocking because the 01 µm PS microplastic is close to the average membrane pore size of 01 µm Through blocking filtration model analysis small PS microplastics satisfy the standard pore blocking because they can penetrate and attach to the inner wall within the membrane pores leading to severe membrane fouling Table 3 For the 10 µm PS microplastics the normalized permeate flux at the Synder membrane which had the smallest estimated membrane pore size did not decrease as much as the SteriLUX and Anodisc membranes meaning that small membrane pores might be advantageous in mitigating fouling Membranes 2022 12 565 9 of 17 Membranes 2022 12 x FOR PEER REVIEW 9 of 17 Figure 3 Particle size distributions in feed and permeate water samples after membrane filtration for a silica particles and b PS microplastics with an average size of 01 μm 32 Effect of Different Sizes of PS Microplastics on Filtration and Treatment Performance We investigated the effects of two different sizes 01 and 10 μm of PS microplastics on filtration and treatment performance to understand their filtration and fouling mechanisms with polymeric and ceramic membranes Figure 4 presents the filtration behaviors of the two different sized PS microplastics for the Synder SteriLUX and Anodisc membranes with the same average pore size of 01 μm as provided by the respective manufacturers A relatively rapid flux decline was observed for small PS microplastics with 01 μm with the normalized permeate flux suddenly decreasing after a few minutes and then consistently maintained for all membranes These observations were attributed to standard or complete pore blocking because the 01 μm PS microplastic is close to the average membrane pore size of 01 μm Through blocking filtration model analysis small PS microplastics satisfy the standard pore blocking because they can penetrate and attach to the inner wall within the membrane pores leading to severe membrane fouling Table 3 For the 10 μm PS microplastics the normalized permeate flux at the Synder membrane which had the smallest estimated membrane pore size did not decrease as much as the SteriLUX and Anodisc membranes meaning that small membrane pores might be advantageous in mitigating fouling Figure 4 Normalized water flux decline of 01 and 10 μm PS microplastics for a Synder b SteriLUX and c Anodisc membranes Table 3 R2 values corresponding to the fouling mechanisms estimated by the blocking model for 01 and 10 μm PS microplastics during the three different membrane filtrations Figure 4 Normalized water flux decline of 01 and 10 µm PS microplastics for a Synder b SteriLUX and c Anodisc membranes Table 3 R2 values corresponding to the fouling mechanisms estimated by the blocking model for 01 and 10 µm PS microplastics during the three different membrane filtrations PS Microplastic Membrane Complete Pore Blocking Standard Pore Blocking Intermediate Pore Blocking Cake Filtration 01 µm Synder 06525 09825 07778 08836 SteriLUX 07583 09997 08946 08908 Anodisc 07813 09525 07735 06617 10 µm Synder 09794 10000 09793 09732 SteriLUX 09724 09999 09657 09565 Anodisc 09603 09997 09751 09839 The changes in turbidity of the 01 and 10 µm PS microplastics with the same concen tration in aqueous solutions during the three different membrane filtrations are shown in Figure S4 in Supplementary Material The initial turbidity values were 1053 05 NTU for 01 µm PS microplastics and 6836 10 NTU for 10 µm PS microplastics while TS concentrations were 69 19 mgL and 46 10 mgL respectively As expected the turbidity of 10 µm PS microplastic was almost completely removed with over 996 removal by all membranes although it showed a slightly lower retention of over 960 for the 01 µm PS microplastics There were no significant changes in the turbidity retention of both PS microplastics depending on membrane type However TS retention increased slightly when the relatively larger membrane pores were within the standard deviation ranges meaning that it would be considered an inappropriate facile and an indirect means of measurement to quantify microplastics and to evaluate their retention in membrane processes The results of the particle size distribution analysis showed that all diameter values D10 D50 and D90 of the 01 µm PS microplastics for the three different membranes decreased slightly after filtration although they decreased significantly for the 10 µm PS microplastics because the average pore size of the three membranes was 01 µm Figure 5 The Anodisc membrane which had relatively larger membrane pores as estimated by PEO retention showed a relatively low retention for the 10 µm PS microplastics even though the smaller size portions within the 10 µm PS microplastics were not completely retained and detected as D90 values in the permeate water samples Membranes 2022 12 565 10 of 17 Membranes 2022 12 x FOR PEER REVIEW 10 of 17 PS Microplastic Membrane Complete Pore Blocking Standard Pore Blocking Intermediate Pore Blocking Cake Filtration 01 μm Synder 06525 09825 07778 08836 SteriLUX 07583 09997 08946 08908 Anodisc 07813 09525 07735 06617 10 μm Synder 09794 10000 09793 09732 SteriLUX 09724 09999 09657 09565 Anodisc 09603 09997 09751 09839 The changes in turbidity of the 01 and 10 μm PS microplastics with the same concentration in aqueous solutions during the three different membrane filtrations are shown in Figure S4 in Supplementary Material The initial turbidity values were 1053 05 NTU for 01 μm PS microplastics and 6836 10 NTU for 10 μm PS microplastics while TS concentrations were 69 19 mgL and 46 10 mgL respectively As expected the turbidity of 10 μm PS microplastic was almost completely removed with over 996 removal by all membranes although it showed a slightly lower retention of over 960 for the 01 μm PS microplastics There were no significant changes in the turbidity retention of both PS microplastics depending on membrane type However TS retention increased slightly when the relatively larger membrane pores were within the standard deviation ranges meaning that it would be considered an inappropriate facile and an indirect means of measurement to quantify microplastics and to evaluate their retention in membrane processes The results of the particle size distribution analysis showed that all diameter values D10 D50 and D90 of the 01 μm PS microplastics for the three different membranes decreased slightly after filtration although they decreased significantly for the 10 μm PS microplastics because the average pore size of the three membranes was 01 μm Figure 5 The Anodisc membrane which had relatively larger membrane pores as estimated by PEO retention showed a relatively low retention for the 10 μm PS microplastics even though the smaller size portions within the 10 μm PS microplastics were not completely retained and detected as D90 values in the permeate water samples Figure 5 Particle size distributions in feed and permeate water samples after membrane filtration for a 01 μm and b 10 μm PS microplastics with the same concentration 33 Effect of Different Types of Microplastics on Filtration and Treatment Performance The effects of two different types of 10 μm microplastics PS and PE on filtration and treatment performance were investigated to understand their filtration and fouling behaviors when using polymeric and ceramic membranes Figure 6 shows the normalized Figure 5 Particle size distributions in feed and permeate water samples after membrane filtration for a 01 µm and b 10 µm PS microplastics with the same concentration 33 Effect of Different Types of Microplastics on Filtration and Treatment Performance The effects of two different types of 10 µm microplastics PS and PE on filtration and treatment performance were investigated to understand their filtration and fouling behaviors when using polymeric and ceramic membranes Figure 6 shows the normalized permeate flux for the 10 µm PS and PE microplastics for the Synder SteriLUX and Anodisc membranes A relatively rapid decline in normalized permeate flux was observed for the PS microplastics at the relatively larger membrane pores SteriLUX and Anodisc membranes while there was only a slight decrease in normalized permeate flux at the Synder membrane For the PE microplastics a rapid normalized permeate flux decline was observed at Synder membrane and gradual decreases at the other two membranes In particular the ceramic membrane Anodisc did not show a severe level of membrane fouling for the PE microplastics These observations could be described through the particle size distribution of the PS and PE microplastics with an average size of 10 µm PS microplastics exhibited the narrowest particle size distribution at around 10 µm while the particle size distribution in PE microplastics was somewhat broader ranging from 008100 µm Figure S5 in Supplementary Material As described in Section 32 smaller microplastics such as the PS microplastics shown in Figure S5 could lead to significant flux reduction However only a gradual flux decline was observed at the Synder membrane of the relatively smaller pores which might be attributable to a shapedependent effect or the properties of the polymer type such as the residual monomer content and may not only be caused by the size of the microplastics ref The fouling mechanisms of the PS and PE microplastics for the three different membranes include complete standard intermediate pore blocking and cake filtration models with R2 values over 095 for all cases presumably due to the relatively larger microplastics Table 4 The initial turbidity values were 6836 10 NTU for the 10 µm PS microplastics and 1201 32 NTU for the 10 µm PE microplastics while TS concentrations were 46 10 mgL and 57 05 mgL respectively Altogether 99 of the turbidity of 10 µm PS and PE microplastics was removed However TS retention increased slightly with increasing membrane pore size Figure S6 in Supplementary Material Although over 90 of TS were removed by all membranes accurate quantification is difficult because the measurement of TS concentration has a high standard deviation range As microplastics are extremely small particles TS measurements showed inconsistent and inaccurate results with other facile and indirect measurement methods as described in Sections 31 and 32 Figure 7 shows that all diameter values of PS and PE microplastics which were measured by particle size distribution analysis decreased significantly after membrane filtration However the Anodisc ceramic membrane was relatively ineffective because the D90 value Membranes 2022 12 565 11 of 17 in the permeate was estimated at 08629 00080 µm for the PE microplastics even though the membrane pores were estimated at 0027300737 µm This was presumably caused by the differently shaped microplastics or broader particle size distribution when compared with the PS microplastics as indicated in Figure S5 Membranes 2022 12 x FOR PEER REVIEW 11 of 17 permeate flux for the 10 μm PS and PE microplastics for the Synder SteriLUX and Anodisc membranes A relatively rapid decline in normalized permeate flux was observed for the PS microplastics at the relatively larger membrane pores SteriLUX and Anodisc membranes while there was only a slight decrease in normalized permeate flux at the Synder membrane For the PE microplastics a rapid normalized permeate flux decline was observed at Synder membrane and gradual decreases at the other two membranes In particular the ceramic membrane Anodisc did not show a severe level of membrane fouling for the PE microplastics These observations could be described through the particle size distribution of the PS and PE microplastics with an average size of 10 μm PS microplastics exhibited the narrowest particle size distribution at around 10 μm while the particle size distribution in PE microplastics was somewhat broader ranging from 008100 μm Figure S5 in Supplementary Material As described in Section 32 smaller microplastics such as the PS microplastics shown in Figure S5 could lead to significant flux reduction However only a gradual flux decline was observed at the Synder membrane of the relatively smaller pores which might be attributable to a shape dependent effect or the properties of the polymer type such as the residual monomer content and may not only be caused by the size of the microplastics ref The fouling mechanisms of the PS and PE microplastics for the three different membranes include complete standard intermediate pore blocking and cake filtration models with R2 values over 095 for all cases presumably due to the relatively larger microplastics Table 4 Figure 6 Normalized water flux decline of 10 μm PS and PE microplastics for a Synder b SteriLUX and c Anodisc membranes Table 4 R2 values corresponding to the fouling mechanisms estimated by the blocking model for 10 μm PS and PE microplastics during the three different membrane filtrations Microplastic Membrane Complete Pore Blocking Standard Pore Blocking Intermediate Pore Blocking Cake Filtration Polystylene PS Synder 09794 10000 09793 09732 SteriLUX 09724 09999 09657 09565 Anodisc 09603 09997 09751 09839 Polyethylene PE Synder 09703 09997 09842 09924 SteriLUX 09827 10000 09813 09791 Anodisc 09675 09998 09870 09874 The initial turbidity values were 6836 10 NTU for the 10 μm PS microplastics and 1201 32 NTU for the 10 μm PE microplastics while TS concentrations were 46 10 mgL and 57 05 mgL respectively Altogether 99 of the turbidity of 10 μm PS and PE microplastics was removed However TS retention increased slightly with increasing membrane pore size Figure S6 in Supplementary Material Although over 90 of TS Figure 6 Normalized water flux decline of 10 µm PS and PE microplastics for a Synder b SteriLUX and c Anodisc membranes Table 4 R2 values corresponding to the fouling mechanisms estimated by the blocking model for 10 µm PS and PE microplastics during the three different membrane filtrations Microplastic Membrane Complete Pore Blocking Standard Pore Blocking Intermediate Pore Blocking Cake Filtration Polystylene PS Synder 09794 10000 09793 09732 SteriLUX 09724 09999 09657 09565 Anodisc 09603 09997 09751 09839 Polyethylene PE Synder 09703 09997 09842 09924 SteriLUX 09827 10000 09813 09791 Anodisc 09675 09998 09870 09874 Membranes 2022 12 x FOR PEER REVIEW 12 of 17 were removed by all membranes accurate quantification is difficult because the measurement of TS concentration has a high standard deviation range As microplastics are extremely small particles TS measurements showed inconsistent and inaccurate results with other facile and indirect measurement methods as described in Sections 31 and 32 Figure 7 shows that all diameter values of PS and PE microplastics which were measured by particle size distribution analysis decreased significantly after membrane filtration However the Anodisc ceramic membrane was relatively ineffective because the D90 value in the permeate was estimated at 08629 00080 μm for the PE microplastics even though the membrane pores were estimated at 0027300737 μm This was presumably caused by the differently shaped microplastics or broader particle size distribution when compared with the PS microplastics as indicated in Figure S5 Figure 7 Particle size distribution in the feed and permeate water samples after membrane filtration for a 10 μm PS and b 10 μm PE microplastics with the same concentration 34 Filtration Behaviors of Microplastics in Identical and Synthetic Wastewater Samples A variety of physicochemical and biological compositions in wastewater samples can impact microplastic filtration behavior and retention performance in membrane filtrations For example dissolved organic matter in synthetic wastewater can exacerbate flux decline via membrane fouling which increases filtration resistance because they contain relatively low concentrations of suspended particles Our filtration and treatment experiments indicated that normalized permeate flux significantly decreased in the presence of microplastics in synthetic wastewater Figures S7S9 Similar normalized permeate fluxes in the presence and absence of wastewater were observed for the 01 μm PS microplastics because the synthetic wastewater which is mostly composed of non particulate dissolved organic matter might not influence the transport of relatively small microplastics In contrast the results of 10 μm PS and PE microplastic experiments performed in synthetic wastewater revealed more rapid flux declines than in the identical PS or PE microplasticcontaining suspensions These observations might have been caused by the aggregation of relatively larger microplastics with dissolved organic matter forming a cake layer on the membrane surface 4748 These results were also attributed to the morphological properties of the microplastics which could not be accurately analyzed via particle size distribution since they were measured as spherical particles No significant changes were observed between the diameter values of the identical and synthetic wastewaters for the 01 μm PS microplastic particles while the slightly decreased diameter values for the 10 μm PS and PE microplastics with the synthetic wastewaters were presumably caused by the physical or morphological properties of the relatively larger microplastics which were affected by several constituents within the Figure 7 Particle size distribution in the feed and permeate water samples after membrane filtration for a 10 µm PS and b 10 µm PE microplastics with the same concentration 34 Filtration Behaviors of Microplastics in Identical and Synthetic Wastewater Samples A variety of physicochemical and biological compositions in wastewater samples can impact microplastic filtration behavior and retention performance in membrane filtra Membranes 2022 12 565 12 of 17 tions For example dissolved organic matter in synthetic wastewater can exacerbate flux decline via membrane fouling which increases filtration resistance because they contain relatively low concentrations of suspended particles Our filtration and treatment experi ments indicated that normalized permeate flux significantly decreased in the presence of microplastics in synthetic wastewater Figures S7S9 Similar normalized permeate fluxes in the presence and absence of wastewater were observed for the 01 µm PS microplastics because the synthetic wastewater which is mostly composed of nonparticulate dissolved organic matter might not influence the transport of relatively small microplastics In contrast the results of 10 µm PS and PE microplastic experiments performed in synthetic wastewater revealed more rapid flux declines than in the identical PS or PE microplastic containing suspensions These observations might have been caused by the aggregation of relatively larger microplastics with dissolved organic matter forming a cake layer on the membrane surface 4748 These results were also attributed to the morphological properties of the microplastics which could not be accurately analyzed via particle size distribution since they were measured as spherical particles No significant changes were observed between the diameter values of the identical and synthetic wastewaters for the 01 µm PS microplastic particles while the slightly decreased diameter values for the 10 µm PS and PE microplastics with the synthetic wastewaters were presumably caused by the physical or morphological properties of the relatively larger microplastics which were affected by several constituents within the synthetic wastewater samples Figures 810 In addition to the effect of dissolved organic matter a slight reduction in the diameter values in the permeate after membrane filtration was observed for the wastewater compared to the identical microplasticcontaining solutions In particular the Anodisc membrane was effective in removing small microplastics because the D90 value in the permeate was the lowest of all the membranes indicating that they almost completely removed the 01 µm PS microplastics from wastewater However the D90 values were not significantly reduced for the 10 µm PS and PE microplastics in synthetic wastewater Regarding the comprehensive perspective for filtration and treatment performance the Synder membrane was the most effective in removing PS microplastic while the Anodisc was able to retain the most PE microplastics This research may offer substantial potential for reducing membrane fouling and increasing the efficiency of microplastic retention techniques simply by using particle size distribution analysis with polymeric and ceramic membranes However the retention performance depends upon the physicochemical and morphological properties of the mi croplastics and wastewater composition As this could limit the application of particle size distribution analysis further research should focus on the development of tools to balance the benefits of efficient microplastic removal against the risks associated with the formation of organic complexation Membranes 2022 12 565 13 of 17 Membranes 2022 12 x FOR PEER REVIEW 13 of 17 synthetic wastewater samples Figures 810 In addition to the effect of dissolved organic matter a slight reduction in the diameter values in the permeate after membrane filtration was observed for the wastewater compared to the identical microplasticcontaining solutions In particular the Anodisc membrane was effective in removing small microplastics because the D90 value in the permeate was the lowest of all the membranes indicating that they almost completely removed the 01 μm PS microplastics from wastewater However the D90 values were not significantly reduced for the 10 μm PS and PE microplastics in synthetic wastewater Regarding the comprehensive perspective for filtration and treatment performance the Synder membrane was the most effective in removing PS microplastic while the Anodisc was able to retain the most PE microplastics This research may offer substantial potential for reducing membrane fouling and increasing the efficiency of microplastic retention techniques simply by using particle size distribution analysis with polymeric and ceramic membranes However the retention performance depends upon the physicochemical and morphological properties of the microplastics and wastewater composition As this could limit the application of particle size distribution analysis further research should focus on the development of tools to balance the benefits of efficient microplastic removal against the risks associated with the formation of organic complexation Figure 8 Particle size distribution in the feed and permeate water samples after membrane filtration with the diameter values of the a identical and b synthetic wastewater for the 01 μm PS microplastics Figure 9 Particle size distribution in the feed and permeate water samples after membrane filtration with the diameter values of the a identical and b synthetic wastewater for the 10 μm PS microplastics Figure 8 Particle size distribution in the feed and permeate water samples after membrane fil tration with the diameter values of the a identical and b synthetic wastewater for the 01 µm PS microplastics Membranes 2022 12 x FOR PEER REVIEW 13 of 17 synthetic wastewater samples Figures 810 In addition to the effect of dissolved organic matter a slight reduction in the diameter values in the permeate after membrane filtration was observed for the wastewater compared to the identical microplasticcontaining solutions In particular the Anodisc membrane was effective in removing small microplastics because the D90 value in the permeate was the lowest of all the membranes indicating that they almost completely removed the 01 μm PS microplastics from wastewater However the D90 values were not significantly reduced for the 10 μm PS and PE microplastics in synthetic wastewater Regarding the comprehensive perspective for filtration and treatment performance the Synder membrane was the most effective in removing PS microplastic while the Anodisc was able to retain the most PE microplastics This research may offer substantial potential for reducing membrane fouling and increasing the efficiency of microplastic retention techniques simply by using particle size distribution analysis with polymeric and ceramic membranes However the retention performance depends upon the physicochemical and morphological properties of the microplastics and wastewater composition As this could limit the application of particle size distribution analysis further research should focus on the development of tools to balance the benefits of efficient microplastic removal against the risks associated with the formation of organic complexation Figure 8 Particle size distribution in the feed and permeate water samples after membrane filtration with the diameter values of the a identical and b synthetic wastewater for the 01 μm PS microplastics Figure 9 Particle size distribution in the feed and permeate water samples after membrane filtration with the diameter values of the a identical and b synthetic wastewater for the 10 μm PS microplastics Figure 9 Particle size distribution in the feed and permeate water samples after membrane fil tration with the diameter values of the a identical and b synthetic wastewater for the 10 µm PS microplastics Membranes 2022 12 565 14 of 17 Membranes 2022 12 x FOR PEER REVIEW 14 of 17 Figure 10 Particle size distribution in the feed and permeate water samples after membrane filtration with the diameter values of the a identical and b synthetic wastewater for the 10 μm PE microplastics 4 Conclusions In this study we used several facile water quality parameters that are widely applied in WWTPs to evaluate the filtration and treatment behaviors of microplastics Our findings indicate that polymeric and ceramic membranes can remove a significant fraction of microplastics contained within the system by adopting the evaluation of facile water quality parameters The reason why some microplastics remain after membrane filtration is still unknown although it appears that a significant proportion of the microplastics remaining in the permeate can be analyzed with particle size distribution analysis The particle size distribution analysis detailed in this study is a promising technique for quantifying the transport of tiny microplastics through wastewater treatment systems Additionally it can improve understanding of microplastic treatment mechanisms and give more precise estimations of the relative contribution to microplastic removal by membranebased processes which can subsequently assist engineers in choosing appropriate membranes for their particular objectives Our results demonstrated that the diameter values obtained from the particle size distribution analysis could significantly promote microplastic retention between the polymeric and ceramic membranes through multiple fouling mechanisms For example microplastics in synthetic wastewater which contains fewer suspended particles and more dissolved organic matter than identical microplasticcontaining solutions have a rapid flux decline curve because organic matter can more effectively limit fouling sources if they contain relatively large microplastics The ceramic membrane was particularly effective at removing PE microplastics but was less effective in retaining PS microplastics These facile and indirect measurement methods can be used to understand the transport of microplastics in membranebased treatment processes as our results suggest that particle size distribution analysis could handle different sizes and types of microplastics Currently however there are only limited options for directly quantifying microplastics associated with wastewaters due to high concentrations of other suspended particles nutrients and organic contaminants Additional studies involving direct quantification for a variety of microplastics are necessary to validate our findings Supplementary Materials The following supporting information can be downloaded at wwwmdpicomxxxs1 Figure S1 Representative diagram of the four fouling mechanisms a complete pore blocking b standard pore blocking c intermediate pore blocking and d cake filtration Figure S2 Volumeweighted particle size distribution and cumulative size distribution curves of a silica particles and b PS microplastics with an average size of 01 μm The xaxis has a logarithmic scale Figure S3 a Turbidity and b TS retention of silica particles and PS microplastics with an average pore size of 01 μm for the Synder SteriLUX and Anodisc Figure 10 Particle size distribution in the feed and permeate water samples after membrane fil tration with the diameter values of the a identical and b synthetic wastewater for the 10 µm PE microplastics 4 Conclusions In this study we used several facile water quality parameters that are widely applied in WWTPs to evaluate the filtration and treatment behaviors of microplastics Our findings indicate that polymeric and ceramic membranes can remove a significant fraction of mi croplastics contained within the system by adopting the evaluation of facile water quality parameters The reason why some microplastics remain after membrane filtration is still unknown although it appears that a significant proportion of the microplastics remaining in the permeate can be analyzed with particle size distribution analysis The particle size distribution analysis detailed in this study is a promising technique for quantifying the transport of tiny microplastics through wastewater treatment systems Additionally it can improve understanding of microplastic treatment mechanisms and give more precise esti mations of the relative contribution to microplastic removal by membranebased processes which can subsequently assist engineers in choosing appropriate membranes for their particular objectives Our results demonstrated that the diameter values obtained from the particle size distribution analysis could significantly promote microplastic retention between the polymeric and ceramic membranes through multiple fouling mechanisms For example microplastics in synthetic wastewater which contains fewer suspended particles and more dissolved organic matter than identical microplasticcontaining solutions have a rapid flux decline curve because organic matter can more effectively limit fouling sources if they contain relatively large microplastics The ceramic membrane was particularly effective at removing PE microplastics but was less effective in retaining PS microplastics These facile and indirect measurement methods can be used to understand the transport of microplastics in membranebased treatment processes as our results suggest that particle size distribution analysis could handle different sizes and types of microplastics Currently however there are only limited options for directly quantifying microplastics associated with wastewaters due to high concentrations of other suspended particles nutrients and organic contaminants Additional studies involving direct quantification for a variety of microplastics are necessary to validate our findings Supplementary Materials The following supporting information can be downloaded at https wwwmdpicomarticle103390membranes12060565s1 Figure S1 Representative diagram of the four fouling mechanisms a complete pore blocking b standard pore blocking c intermediate pore blocking and d cake filtration Figure S2 Volumeweighted particle size distribution and cumulative size distribution curves of a silica particles and b PS microplastics with an average size of 01 µm The xaxis has a logarithmic scale Figure S3 a Turbidity and b TS retention of silica particles and PS Membranes 2022 12 565 15 of 17 microplastics with an average pore size of 01 µm for the Synder SteriLUX and Anodisc membranes Figure S4 a Turbidity and b TS retention of 01 µm and 10 µm PS microplastics with an average pore size of 01 µm for the Synder SteriLUX and Anodisc membranes Figure S5 Volumeweighted particle size distribution and cumulative size distribution curves of a PS microplastic and b PE microplastics with an average size of 10 µm The xaxis has a logarithmic scale Figure S6 a Turbidity and b TS retention of 10 µm polystyrene PS and polyethylene PE microplastics with an average pore size of 10 µm for the Synder SteriLUX and Anodisc membranes Figure S7 Normalized water flux decline of 01 µm PS microplastics in identical and synthetic wastewater for a Synder b SteriLUX and c Anodisc membranes Figure S8 Normalized water flux decline of 10 µm PS microplastics in identical and synthetic wastewater for a Synder b SteriLUX and c Anodisc membranes Figure S9 Normalized water flux decline of 10 µm PE microplastics in identical and synthetic wastewater for a Synder b SteriLUX and c Anodisc membranes Author Contributions HK Conceptualization Methodology Formal analysis Investigation Writing original draft review editing CP Resources Supervision Funding acquisition Writingreview editing All authors have read and agreed to the published version of the manuscript Funding This work was supported by the National Research Foundation of Korea NRF grant funded by the Korean government Ministry of Science and ICT No 2021R1C1C1006444 and was also supported by the National RD Program through the National Research Foundation of Korea NRF funded by the Ministry of Science and ICT No 2020M3H4A3106360 Institutional Review Board Statement Not applicable Informed Consent Statement Not applicable Data Availability Statement Not applicable Conflicts of Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper References 1 Prata JC Microplastics in wastewater State of the knowledge on sources fate and solutions Mar Pollut Bull 2018 129 262265 CrossRef PubMed 2 Li J Liu H Chen JP Microplastics in freshwater systems A review on occurrence environmental effects and methods for microplastics detection Water Res 2018 137 362374 CrossRef PubMed 3 Cheung PK Fok L Characterisation of plastic microbeads in facial scrubs and their estimated emissions in Mainland China Water Res 2017 122 5361 CrossRef PubMed 4 Fendall LS Sewell MA Contributing to marine pollution by washing your face Microplastics in facial cleansers Mar Pollut Bull 2009 58 12251228 CrossRef 5 Sun J Dai X Wang Q van Loosdrecht MCM Ni BJ Microplastics in wastewater treatment plants Detection occurrence and removal Water Res 2019 152 2137 CrossRef 6 Ziajahromi S Neale PA Rintoul L Leusch FDL Wastewater treatment plants as a pathway for microplastics Development of a new approach to sample wastewaterbased microplastics Water Res 2017 112 9399 CrossRef 7 Murphy F Ewins C Carbonnier F Quinn B Wastewater Treatment Works WwTW as a Source of Microplastics in the Aquatic Environment Environ Sci Technol 2016 50 58005808 CrossRef 8 Ali I Ding T Peng C Naz I Sun H Li J Liu J Micro and nanoplastics in wastewater treatment plants Occurrence removal fate impacts and remediation technologiesA critical review Chem Eng J 2021 423 130205 CrossRef 9 Talvitie J Mikola A Koistinen A Setälä O Solutions to microplastic pollutionRemoval of microplastics from wastewater effluent with advanced wastewater treatment technologies Water Res 2017 123 401407 CrossRef 10 Dris R Gasperi J Rocher V Saad M Renault N Tassin B Microplastic contamination in an urban area A case study in Greater Paris Environ Chem 2015 12 592599 CrossRef 11 Talvitie J Heinonen M Pääkkönen JP Vahtera E Mikola A Setälä O Vahala R Do wastewater treatment plants act as a potential point source of microplastics Preliminary study in the coastal Gulf of Finland Baltic Sea Water Sci Technol 2015 72 14951504 CrossRef PubMed 12 Talvitie J Mikola A Setälä O Heinonen M Koistinen A How well is microlitter purified from wastewaterA detailed study on the stepwise removal of microlitter in a tertiary level wastewater treatment plant Water Res 2017 109 164172 CrossRef PubMed 13 Lares M Ncibi MC Sillanpaa M Sillanpaa M Occurrence identification and removal of microplastic particles and fibers in conventional activated sludge process and advanced MBR technology Water Res 2018 133 236246 CrossRef PubMed Membranes 2022 12 565 16 of 17 14 Maliwan T Pungrasmi W Lohwacharin J Effects of microplastic accumulation on floc characteristics and fouling behavior in a membrane bioreactor J Hazard Mater 2021 411 124991 CrossRef 15 Magni S Binelli A Pittura L Avio CG Della Torre C Parenti CC Gorbi S Regoli F The fate of microplastics in an Italian Wastewater Treatment Plant Sci Total Environ 2019 652 602610 CrossRef 16 Jeong Y Lee S Hong S Park C Preparation characterization and application of lowcost pyrophyllitealumina composite ceramic membranes for treating lowstrength domestic wastewater J Membr Sci 2017 536 108115 CrossRef 17 Cha M Kim S Park C Recent advances and future potential of anaerobic ceramic membrane bioreactors for wastewater treatment A review Membr Water Treat 2020 11 3139 18 Cha M Boo C Song IH Park C Investigating the potential of ammonium retention by graphene oxide ceramic nanofiltration membranes for the treatment of semiconductor wastewater Chemosphere 2022 286 131745 CrossRef 19 Jeong Y Kim Y Jin Y Hong S Park C Comparison of filtration and treatment performance between polymeric and ceramic membranes in anaerobic membrane bioreactor treatment of domestic wastewater Sep Purif Technol 2018 199 182188 CrossRef 20 Dekiff JH Remy D Klasmeier J Fries E Occurrence and spatial distribution of microplastics in sediments from Norderney Environ Pollut 2014 186 248256 CrossRef 21 Dümichen E Eisentraut P Bannick CG Barthel AK Senz R Braun U Fast identification of microplastics in complex environmental samples by a thermal degradation method Chemosphere 2017 174 572584 CrossRef PubMed 22 Fries E Dekiff JH Willmeyer J Nuelle MT Ebert M Remy D Identification of polymer types and additives in marine microplastic particles using pyrolysisGCMS and scanning electron microscopy Environ Sci Process Impacts 2013 15 19491956 CrossRef PubMed 23 Nuelle MT Dekiff JH Remy D Fries E A new analytical approach for monitoring microplastics in marine sediments Environ Pollut 2014 184 161169 CrossRef PubMed 24 Park D Kim D Lim HJ Park C Chua B Lee JW Yoon Y Son A Chia seedassisted separation and detection of polyvinyl chloride microplastics in water via gas chromatography mass spectrometry Chemosphere 2021 273 129599 CrossRef 25 Browne MA Crump P Niven SJ Teuten E Tonkin A Galloway T Thompson R Accumulation of Microplastic on Shorelines Woldwide Sources and Sinks Environ Sci Technol 2011 45 91759179 CrossRef 26 Löder MGJ Kuczera M Mintenig S Lorenz C Gerdts G Focal plane array detectorbased microFouriertransform infrared imaging for the analysis of microplastics in environmental samples Environ Chem 2015 12 563581 CrossRef 27 Mintenig SM IntVeen I Löder MGJ Primpke S Gerdts G Identification of microplastic in effluents of waste water treatment plants using focal plane arraybased microFouriertransform infrared imaging Water Res 2017 108 365372 CrossRef 28 Araujo CF Nolasco MM Ribeiro AMP RibeiroClaro PJA Identification of microplastics using Raman spectroscopy Latest developments and future prospects Water Res 2018 142 426440 CrossRef 29 ErniCassola G Gibson MI Thompson RC ChristieOleza JA Lost but Found with Nile Red A Novel Method for Detecting and Quantifying Small Microplastics 1 mm to 20 mu m in Environmental Samples Environ Sci Technol 2017 51 1364113648 CrossRef 30 RochaSantos T Duarte AC A critical overview of the analytical approaches to the occurrence the fate and the behavior of microplastics in the environment TrAC Trends Anal Chem 2015 65 4753 CrossRef 31 Shim WJ Hong SH Eo SE Identification methods in microplastic analysis A review Anal Methods 2017 9 13841391 CrossRef 32 Jung JW Kim S Kim YS Jeong S Lee J Tracing microplastics from raw water to drinking water treatment plants in Busan South Korea Sci Total Environ 2022 825 154015 CrossRef PubMed 33 Schymanski D Goldbeck C Humpf HU Fürst P Analysis of microplastics in water by microRaman spectroscopy Release of plastic particles from different packaging into mineral water Water Res 2018 129 154162 CrossRef PubMed 34 Nava V Frezzotti ML Leoni B Raman Spectroscopy for the Analysis of Microplastics in Aquatic Systems Appl Spectrosc 2021 75 13411357 CrossRef PubMed 35 Elert AM Becker R Duemichen E Eisentraut P Falkenhagen J Sturm H Braun U Comparison of different methods for MP detection What can we learn from them and why asking the right question before measurements matters Environ Pollut 2017 231 12561264 CrossRef 36 HidalgoRuz V Gutow L Thompson RC Thiel M Microplastics in the Marine Environment A Review of the Methods Used for Identification and Quantification Environ Sci Technol 2012 46 30603075 CrossRef 37 Schwarzer M Brehm J Vollmer M Jasinski J Xu C Zainuddin S Fröhlich T Schott M Greiner A Scheibel T et al Shape size and polymer dependent effects of microplastics on Daphnia magna J Hazard Mater 2021 426 128136 CrossRef 38 Caputo F Vogel R Savage J Vella G Law A Della Camera G Hannon G Peacock B Mehn D Ponti J et al Measuring particle size distribution and mass concentration of nanoplastics and microplastics Addressing some analytical challenges in the submicron size range J Colloid Interface Sci 2021 588 401417 CrossRef 39 Uurasjärvi E Hartikainen S Setälä O Lehtiniemi M Koistinen A Microplastic concentrations size distribution and polymer types in the surface waters of a northern European lake Water Environ Res 2020 92 149156 CrossRef Membranes 2022 12 565 17 of 17 40 Jeong Y Cho K Kwon EE Tsang YF Rinklebe J Park C Evaluating the feasibility of pyrophyllitebased ceramic membranes for treating domestic wastewater in anaerobic ceramic membrane bioreactors Chem Eng J 2017 328 567573 CrossRef 41 Kim S Park C Potential of ceramic ultrafiltration membranes for the treatment of anionic surfactants in laundry wastewater for greywater reuse J Water Process Eng 2021 44 102373 CrossRef 42 Kim S Park C Fouling behavior and cleaning strategies of ceramic ultrafiltration membranes for the treatment and reuse of laundry wastewater J Water Process Eng 2022 48 102840 CrossRef 43 Rana D Matsuura T Narbaitz RM Novel hydrophilic surface modifying macromolecules for polymeric membranes Polyurethane ends capped by hydroxy group J Membr Sci 2006 282 205216 CrossRef 44 Wang F Tarabara VV Pore blocking mechanisms during early stages of membrane fouling by colloids J Colloid Interface Sci 2008 328 464469 CrossRef PubMed 45 Ho CC Zydney AL A Combined Pore Blockage and Cake Filtration Model for Protein Fouling during Microfiltration J Colloid Interface Sci 2000 232 389399 CrossRef 46 Boerlage SFE Kennedy MD Dickson MR ElHodali DEY Schippers JC The modified fouling index using ultrafiltration membranes MFIUF Characterisation filtration mechanisms and proposed reference membrane J Membr Sci 2002 197 121 CrossRef 47 Guo X Li Q Hu W Gao W Liu D Ultrafiltration of dissolved organic matter in surface water by a polyvinylchloride hollow fiber membrane J Membr Sci 2009 327 254263 CrossRef 48 Lin CF Lin AYC Chandana PS Tsai CY Effects of mass retention of dissolved organic matter and membrane pore size on membrane fouling and flux decline Water Res 2009 43 389394 CrossRef Citation Hamoudi L Akretche DE Hadadi A Amrane A Mouni L Comparative Study of Ceramic Membranes Developed on Different Algerian Natural Clays for IndustrialEffluent Filtration Minerals 2023 13 273 https doiorg103390min13020273 Academic Editors Nevenka Rajic and Jelena Pavlovic Received 16 January 2023 Revised 10 February 2023 Accepted 14 February 2023 Published 15 February 2023 Copyright 2023 by the authors Licensee MDPI Basel Switzerland This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution CC BY license https creativecommonsorglicensesby 40 minerals Article Comparative Study of Ceramic Membranes Developed on Different Algerian Natural Clays for IndustrialEffluent Filtration Leyla Hamoudi 1 Djamel Eddine Akretche 1 Amina Hadadi 2 Abdeltif Amrane 3 and Lotfi Mouni 2 1 Laboratory of Hydrometallurgy and Inorganic Molecular Chemistry Faculty of Chemistry University of Science and Technology Houari Boumediene BP 32 El Alia Bab Ezzouar 16111 Algeria 2 Laboratoire de Gestion et Valorisation des Ressources Naturelles et Assurance Qualité Faculté SNVST Université de Bouira Bouira 10000 Algeria 3 Ecole Nationale Supérieure de Chimie de Rennes CNRS ISCRUMR6226 Université de Rennes F35000 Rennes France Correspondence abdeltifamraneunivrennes1fr AA lmouniunivbouiradz LM Abstract This research is based on the deposition of ceramic membranes made from Algerian clays within tubular supports The major objective is to compare the mechanical strength and water permeability of the developed supports The membranes made from the same clays are then examined in terms of their application areas and efficacy in treating a localcheese effluent The study of these clays demonstrates that the tubular supports made from Aomar clay are more robust than those obtained from kaolin and bentonite This was due to the higher calcination temperature which was 1000 C for Aomar and kaolin clays and 800 C for bentonite However the tubular support based on kaolin has the maximum water permeability 146009 Lm2hbar In addition the permeability tests performed on the membranes deposited on these clays indicate that those of bentonite and Aomar clay are ultrafiltration membranes whereas the membrane obtained from kaolin is a microfiltration membrane We demonstrated that the three membranes show high efficiency for the clarification and retention of multiplepollutant loads of a localcheese effluent Keywords Algerian clays ceramic membranes microfiltration and ultrafiltration membranes industrialeffluent treatment 1 Introduction Water is a vital resource for human existence and progress in a variety of industries such as agriculture and manufacturing Therefore it must be maintained clean and func tional Nonetheless the most technologically advanced human activities have led to its contamination and unfortunately it is discharged into the environment as effluents without any prior treatment 12 According to their composition these effluents are poisonous and their use is hazardous to ordinary living While certain effluents pickling bath surface treatment etc pose major pollution concerns others such as those from the agrifood industry are highly polluting yet readily biodegradable and profitable dairies sugar facto ries starch processing fruit and vegetable conversion etc 3 The color of other effluents such as those from the paper andor textile industries has a considerable aesthetic influ ence on the aquatic environment Consequently it is essential to treat them prior to their release into the natural environment In the dairy industry rejected waters are contaminated by cleaning washing and disinfecting chemicals sterilizers and other dairy products 45 all of this pollution demonstrates that dairy effluents are substantially polluted with both mineral and organic pollutants posing a significant threat to the environment when discharged untreated into aquatic receiving media 46 The purification of wastewaters entails enhancing their physicochemical and biological properties so that the treated water fulfills the needed criteria 78 In this regard a number Minerals 2023 13 273 httpsdoiorg103390min13020273 httpswwwmdpicomjournalminerals Minerals 2023 13 273 2 of 19 of procedures have been used for the treatment of wastewater including physicochemical processes such as adsorption 912 coagulationflocculation 1316 and advanced oxi dation processes 17 microorganismbased biological treatment was also used to reduce carbon nitrogen and phosphate contamination notably in dairy effluents 18 methods of membrane separation using the osmosis phenomena 19 and membranefiltration processes such as nanofiltration ultrafiltration and microfiltration membranes 20 Membrane filtration is an increasingly popular technology for treating wastewater due to its high efficiency and versatility in removing various contaminants This technology involves the use of semipermeable membranes to separate solids and dissolved substances from wastewater Over the past few decades significant progress has been made in the development and application of membranefiltration systems making it a viable alterna tive to traditional treatment methods such as sedimentation and chemical precipitation According to recent studies 2122 membrane filtration has shown promising results in terms of waterquality improvement and cost effectiveness The separation mechanism in membrane filtration is based on the sizeexclusion prin ciple where the pores in the membrane act as a physical barrier to separate contaminants from the wastewater The pore size of the membrane can be adjusted to target specific contaminants such as bacteria viruses and organic matter The separation mechanism can be further enhanced by combining membrane filtration with other treatment processes such as coagulation and flocculation 23 The efficiency of the separation process is also influenced by various factors including the pressure difference across the membrane the temperature and pH of the wastewater and the type of membrane material used 24 Studies have shown that the use of membrane filtration in wastewater treatment can result in high removal rates for various contaminants including pathogens eg Escherichia coli and coliphages 22 nutrients eg nitrogen and phosphorus 25 and emerging contaminants eg pharmaceuticals and personalcare products 26 The separation mechanism in membrane filtration provides a sustainable and costeffective solution for addressing the growing challenges in wastewater treatment The increasing demand for clean water and the stringent regulations for water quality have driven the need for further research and development in the field of membrane filtration Microfiltration MF and ultrafiltration UF are two commonly used membrane filtration processes for wastewater treatment MF is a lowpressure filtration process that uses membranes with pore sizes ranging from 01 to 10 µm The main goal of MF is to remove suspended solids and colloidal particles from the wastewater resulting in the improvement of water clarity and turbidity 27 UF on the other hand uses membranes with pore sizes ranging from 001 to 01 µm and operates at higher pressures than MF The objective of UF is to remove dissolved substances including proteins organic molecules and pathogens from the wastewater 28 Both MF and UF have been widely applied in various wastewatertreatment appli cations such as municipalwastewater treatment industrialwastewater treatment and desalination MF and UF are also compatible with other treatment processes such as adsorption and oxidation which can further improve the removal efficiency of contami nants 29 The use of MF and UF in wastewater treatment has been shown to result in high removal rates for various contaminants such as bacteria organic matter and nutrients The combination of MF and UF provides a flexible and costeffective solution for addressing the complex challenges in wastewater treatment Ceramic membranes are a type of membranefiltration technology that is gaining increasing attention for its potential in wastewater treatment Ceramic membranes are made from inorganic materials such as alumina zirconia and titania and are known for their high mechanical strength and chemical stability 30 Compared to polymeric membranes ceramic membranes offer several advantages such as higher temperature and pH tolerance better resistance to fouling and longer membrane life 31 However ceramic membranes also have some disadvantages such as high cost low flexibility and limited availability of pore sizes 32 Furthermore ceramic membranes have a relatively high Minerals 2023 13 273 3 of 19 permeation resistance which can result in lower permeate flux compared to polymeric membranes 33 Despite these limitations ceramic membranes have shown promising results in wastewatertreatment applications particularly in the removal of challenging contaminants such as heavy metals organics and pathogens 30 In comparison to polymeric membranes ceramic membranes have been shown to provide higher removal efficiency and longterm stability in various wastewatertreatment processes Overall ceramic membranes are a promising technology for wastewater treatment offering high performance and durability while also addressing some of the challenges associated with polymeric membranes Recently the use of clay as a raw material for synthesizing ceramic membranes has gained attention as a sustainable and lowcost alternative to traditional ceramic materials Clay is abundant and widely available making it an attractive option for largescale pro duction of ceramic membranes Additionally clay has good plasticity and can be molded into various shapes and sizes providing flexibility in the design of ceramic membranes 34 Studies have shown that claybased ceramic membranes can provide high performance in various wastewatertreatment applications including the removal of pathogens organic pollutants and heavy metals 35 Furthermore claybased ceramic membranes have demonstrated good mechanical strength and chemical stability making them a promising alternative to traditional ceramic membranes The use of clay as a raw material for syn thesizing ceramic membranes has the potential to make this technology more accessible and costeffective while also providing high performance and durability in wastewater treatment applications Further research is needed to optimize the synthesis process and enhance the performance of claybased ceramic membranes making them a viable option for wider implementation in wastewater treatment The aim of this work is to evaluate the effectiveness of three synthetized claybased ceramic membranes in purifying cheese effluent based on their performance compared to the standards set by the World Health Organization WHO as referenced in the official journal of the Algerian Republic For this purpose three Algerian clays namely bentonite from northwestern Algeria kaolin from northeastern Algeria and clay from Aomar in the central north of the country were selected for the study to our knowledge such work has never been undertaken before 2 Materials and Methods 21 Raw Materials Local clays Algerian from various regions are used to develop tubular supports including bentonite from Maghnia located in northwestern Algeria kaolin from Tamazert located in northeastern Algeria and clay from Aomar in the central north of the country which is used in the production of red brick An Xrayfluorescencespectroscopy study using a spectrometer S8 TIGER Bruker Germany was undertaken to identify the chemical composition of each kind of clay 22 Preparation of Ceramic Paste The optimal formulation of ceramic pastes using various types of clay has been developed to possess the requisite rheological characteristics including homogeneity cohe sion porosity and extrusiondeformation capacity ensuring their suitability for intended applications 36 Each type of clay is sieved through a 75 µm sieve mixed with water and organic additives starch with the chemical formula C6H10O5nfrom FlukaBiochemika methocel which is a cellulosic derivative with the chemical name hydroxypropyl methylcellulose and from The Dow Chemical Company amijel which is a derivative product consisting of pregelled starch Cplus12072 cerestar These organic additives play a vital role in tubularsupport shaping and providing acceptable physical and mechanical qualities after sintering 37 Minerals 2023 13 273 4 of 19 23 Extrusion of Ceramic Paste Extrusion of the previously produced ceramic paste is used to construct tubular supports It is based on the idea of compressing the paste in a cylinder which is put on another cylindrical molded component to produce singlechannel tubular supports with welldefined diameters 3839 Following extrusion the supports are air dried for 6 days before being heat treated in a furnace Nabertherm GmbH Lilienthal Germany using a twostage thermal program Figure 1ac show the experimental procedures for this preparation including all of the tubular supports produced for each kind of clay the thermal program used for sintering them and a schematic depiction of the thermal program used for sintering the tubular supports Minerals 2022 12 x FOR PEER REVIEW 4 of 17 Each type of clay is sieved through a 75 µm sieve mixed with water and organic additives starch with the chemical formula C6H10O5nfrom FlukaBiochemika methocel which is a cellulosic derivative with the chemical name hydroxypropyl methylcellulose and from The Dow Chemical Company amijel which is a derivative product consisting of pregelled starch Cplus12072 cerestar These organic additives play a vital role in tub ularsupport shaping and providing acceptable physical and mechanical qualities after sintering 37 23 Extrusion of Ceramic Paste Extrusion of the previously produced ceramic paste is used to construct tubular sup ports It is based on the idea of compressing the paste in a cylinder which is put on another cylindrical molded component to produce singlechannel tubular supports with wellde fined diameters 3839 Following extrusion the supports are air dried for 6 days before being heat treated in a furnace Nabertherm GmbH Lilienthal Germany using a two stage thermal program Figure 1ac show the experimental procedures for this prepara tion including all of the tubular supports produced for each kind of clay the thermal program used for sintering them and a schematic depiction of the thermal program used for sintering the tubular supports drying in the air dry and high temperature sintering tubular ceramic supports extrusion after restingand obtaining tubular supports let the ceramic paste rest for 24 hours Obtaining a ceramic paste mixing the mixture with water mix of 84 of clay 4 of Amijel 4 of Méthocel 8 of Amidon a b For tubular supports of bentonite 345 385 115 565 525 3 hours 0 800C 2Cminutes Time min Temperature C 1000C 5Cminutes 250 C 2 hours 3 hours 235 For tubular supports of Kaolin and Aomar clays 20 C Compressor Feed tank Valve Manometer Membrane support Water pump Filtration module Permeate c d Figure 1 Representative figures of the a flowchart of the main procedures followed for the elabora tion of tubular ceramic supports b tubular supports obtained for each type of clay c schematic representation of the thermal program followed for the sintering of the tubular supports and d schematic representation of used filtration pilot Minerals 2023 13 273 5 of 19 24 Mechanical and Physical Properties of Tubular Supports before and after Sintering The outer and inner diameters lengths and thicknesses of the elaborated tubular supports were measured with a caliper before during and after drying and sintering to determine their physical properties To regulate the resistance of the tubular supports the mechanical properties of the supports produced after sintering were determined by measuring their mechanical resis tance using the threepoint bending technique with a TLSTechlabsystem instrument Lezo Spain The objective of this measurement is to position a sample of a solid material on two simple supports and apply a force to the samples center until it fractures and then read the breakingstrength data 25 Test of Water Permeability for Tubular Supports Following sintering the tubular supports were cut to 15 cm and tested for permeability using a closedcircuit filtering pilot see Figure 1d This pilot consists of a feed tank a water pump a filter module including the support two pressure regulators and a compressor used to apply varying pressures 26 Membrane Preparation and Deposition Our membranes were manufactured by preparing a slip consisting of a mass percent age W combination of 30 W polyvinyl alcohol gel 12 W PVA in water 65 W water and 5 W clay powder sieved through 40 µm 39 Slipcasting is the technique used for the deposition of membranes of each type of clay It consists of placing the tubular supports which are blocked at one end in a vertical position and then filling them with the slip during a specific time of engobing then allowing them to air dry for 24 h to allow the excess slip to drip off The membranes placed on the inner surface of the tubular supports are consolidated using heat treatment at the optimal sintering temperature for each membrane 750 C for the bentonitebased membrane and 900 C for the kaolin and Aomarclaybased membranes It is essential to note that the optimal sintering temperature for each membrane was determined based on their homogeneity and adhesion to the inner walls of the tubular supports 27 Determination of the Field of Application of Each Membrane Determining the area of application for ceramic membranes is a crucial stage in the membranefiltration process in order to determine the type of the effluent that will be filtered on each membrane 37 Figure 1d depicts a filtration pilot used to test the permeability to pure water of our newly designed membranes We were able to identify the area of application for our membranes based on the findings obtained by comparing the volumeflowdensity order with that of different membrane techniques described in the literature 37 28 The Efficiency of Membranes for Filtration of a Cheese Effluent Filtration of a cheese effluent from the TARTINO cheese situated in the Rouiba indus trial zone was used to evaluate the performance of our newly designed membranes central north of Algeria The effluent was injected into the feed tank while the support containing the ceramic membrane was installed within the module Figure 1d and exposed to varying pressures of effluent circulation Following filtration various physicochemical pollution characteristics were analyzed for each permeate collected in Erlenmeyer flasks for each applied pressure as well as the unfiltered effluent returned to the feed tank Table 1 depicts the pollutant metrics evaluated and their limit levels regarding Algerian industrial discharges Minerals 2023 13 273 6 of 19 Table 1 Limit values of some physicochemical parameters of pollution in industrial rejection in Algeria Parameters Temperature T C pH SP mgL Conductiviy µSCm Turbidity NTU Phosphates mgL Nitrates mgL Nitrite mgL Ammonium mgL BOD5 mgL COD mgL Limit values 30C 6585 35 2500 80 10 30 3 5 35 120 SP Suspended particles BOD5 Biologicaloxygen demand COD Chemicaloxygen demand Minerals 2023 13 273 7 of 19 3 Results and Discussions 31 Characterization of the Raw Materials The findings produced by the Xrayfluorescence analysis are stated in the oxide equivalent for each atom present in each clay see Table 2 The Xrayfluorescence analysis of the three clays showed that they are composed of several metal oxides with different proportions The silicates and alumina form the main composition of each clay studied This outcome aligns with the findings in the study of natural zeolitebased clay ceramic membranes 40 32 Physical and Mechanical Characteristics of Tubular Supports Table 3 shows the physical and mechanical properties of tubular supports produced without membrane from each kind of clay The table demonstrates that the fabricated tubular supports underwent volume shrink age during air drying represented by VSd and volume shrinkage during sintering rep resented by VSs The tubular supports prepared on the basis of bentonite have a higher volume shrinkage compared to those based on the kaolin and Aomar clays These two phenomena linked to VSd and VSs have been explained in the literature by the disappear ance of the water used for the production of ceramic pastes during drying in addition to the removal of organic additives included in the paste during sintering 41 Furthermore mechanical resistance to ceramic while drying as well as the disappearance of bending reveal that tubular supports made of Aomar clay are more robust than those made of kaolin and bentonite 2102 Mpa 186 Mpa and 1384 Mpa respectively This finding is explained by the difference in the rate of lime CaO in the three clays which is larger in Aomar clay 1318 compared to Kaolin 615 and bentonite 237 Indeed recent studies have demonstrated that increasing the quantity of lime in clays enhances thermal stability and mechanical strength 4243 33 Determination of the Water Permeability of Tubular Supports The permeability of the supports based on each clay was measured by applying the wellknown relationship 1 44 to investigate the fluctuation of the permeation flux with distilled water through the support until it reaches stability Figure 2 shows the Studys findings for each kind of clay Jw V S t 1 where Jw is the water permeate flux V the volume collected after each 10 min S represents the support surface S 2πrL and t is the time required to collect the same volume of water after every 10 min The data in Figure 2 clearly illustrate the fact that the permeate flow diminishes with time in all examined tubular supports and stabilizes after 40 min for each applied pressure This fluxstability finding is consistent with previous research which reveals that the permeation flux often stabilizes within 30 or 40 min 373945 Using the relation 2 46 we were able to calculate the water permeability Lp for the tubular supports that corresponded to each kind of clay via the graphical depiction of the flux fluctuation as a function of applied pressure Jw fP Lp Jw P 2 were P is the effective transmembranepressure difference and Jw the steady flow of the applied pressure The findings reveal that the flux variation as a function of pressure is linear for all of the supports investigated Furthermore the permeability computed for each support see Figure 3a shows that kaolin has a larger permeability than the Aomar and bentonite clays 146009 Lm2 bar 57073 Lm2 h bar and 8311 Lm2 bar respectively Minerals 2023 13 273 8 of 19 Table 2 Chemical composition of the clays in mass percentageW Designation SiO2 Al2O3 CaO Fe2O3 MgO TiO2 Na2O P2O5 K2O Mn2O3 SO3 Bentonite 6329 1990 237 197 292 015 238 004 191 005 001 Aomar clay 5183 1685 1318 869 196 099 135 019 202 016 017 Kaolin 5785 2425 615 349 042 038 016 012 346 004 011 Table 3 Physicalmechanical characteristics of the tubular supports obtained from each type of clay Tubular Support Length L Outside Diameter Dout and Inside Dins Just after Extrusion Length L Outside Diameter Dout and Inside Dins after Drying Better Sintering Temperature Length L Outside Diameter Dout and Inside Dins after Sintering Volumetric Shrinkage after Drying VSd and after Sintering VSs Mechanical Resistance to Bending MPa Bentonitebased support L 190 mm Dout 14 mm Dins 9 mm L 182 mm Dout 11 mm Dins 65 mm 800 C L 172 mm Dext 10 mm Dins 6 mm VSd 247 VSs 141 1384 AomarClayBased support L 190 mm Dout 14 mm Dins 9 mm L 188 mm Dout 13 mm Dins 8 mm 1000 C L 187 mm Dout 125 mm Dins 75 mm VSd 812 VSs 436 2102 KaolinBased support L 190 mm Dout 14 mm Dins 9mm L 185 mm Dout 12 mm Dins 7 mm 1000 C L 183 mm Dout 11 mm Dins 6 mm VSd 1654 VSs 932 186 Minerals 2023 13 273 9 of 19 1 2 Minerals 2022 12 x FOR PEER REVIEW 8 of 17 10 20 30 40 50 60 800 1200 1600 2000 2400 2800 3200 3600 4000 Jw Lhm2 time minute for 05 bar for 1 bar for 15 bar for 2 bar c Figure 2 Variation in the permeation flux with distilled water as a function of time for the a sup port based on bentonite b support based on Aomar clay and c support based on kaolin Using the relation 2 46 we were able to calculate the water permeability Lp for the tubular supports that corresponded to each kind of clay via the graphical depiction of the flux fluctuation as a function of applied pressure Jw fP Lp Jw ΔP 2 were P is the effective transmembranepressure difference and Jw the steady flow of the applied pressure The findings reveal that the flux variation as a function of pressure is linear for all of the supports investigated Furthermore the permeability computed for each support see Figure 3a shows that kaolin has a larger permeability than the Aomar and bentonite clays 146009 Lm2 bar 57073 Lm2 h bar and 8311 Lm2 bar respectively Figure 2 Variation in the permeation flux with distilled water as a function of time for the a support based on bentonite b support based on Aomar clay and c support based on kaolin Minerals 2023 13 273 10 of 19 Minerals 2022 12 x FOR PEER REVIEW 9 of 17 05 10 15 20 0 500 1000 1500 2000 2500 3000 Pressures bars 3 2 a Lp 8311 Lm2hbar b Lp 57073 Lm2hbar c Lp 146009 Lm2hbar Jw Lh m2 1 a 00 05 10 15 20 25 30 35 40 0 200 400 600 800 1000 1200 1400 1600 1800 6 5 4 a Lp 7169 Lm2hbar b Lp 1512 Lm2hbar c Lp 54737 Lm2hbar Jw Lh m2 Pressures bars b Figure 3 a Variation of the flux as a function of the applied pressure for the support based on 1 bentonite 2 Aomar clay 3 kaolin and for the membranes developed based on b 4 bentonite 5 Aomar clay and 6 kaolin 34 The Water Permeability of Membranes Developed The permeability of membranes produced from the investigated clays was calculated using the same approach as the permeability of the previously indicated supports The acquired findings are shown in Figure 3b The various domains of application of membranes ultrafiltration microfiltration and nanofiltration have been characterized in the literature based on permeability to dis tilled water and appliedpressurevalue intervals 3747 In this regard the values obtained for the Lp permeability of different membranes in Figure 3b indicate that the membranes based on bentonite and Aomar clays are ultrafil tration membranes with values of Lp 7169 and 1512 Lm2hbar respectively and the membrane based on kaolin is a microfiltration membrane with a value of Lp 54737 Lm2hbarThe comparison of our findings with prior studies on natural zeolitebased ce ramic membranes highlights the application of these membranes for ultrafiltration and nanofiltration 354448 These studies have demonstrated their efficacy in filtering saline water and retaining monovalent and bivalent metals 35 The Study of the Efficiency of Our Membranes in the Filtration of a Local Effluent Our filtering membranes are specifically aimed at filtration of a localcheese effluent This is because the effluent needs to undergo special treatment to reduce its organic and inorganic contaminant levels prior to being released into the environment 4749 Figure 4 shows the difference in appearance of the effluent before and after filtration with varying transmembrane pressures on the developed membranes as well as the liq uid in the feed tank The images reveal that before filtration the effluent has a white tint with high turbidity However after filtration through the microfiltration and ultrafiltra tion membranes at various pressures the resulting permeate is clear and transparent in dicating the effectiveness of the membraned in clarifying the effluent The dark color and high turbidity of the liquid in the feed tank also supports this result 1 Figure 3 a Variation of the flux as a function of the applied pressure for the support based on 1 bentonite 2 Aomar clay 3 kaolin and for the membranes developed based on b 4 bentonite 5 Aomar clay and 6 kaolin 34 The Water Permeability of Membranes Developed The permeability of membranes produced from the investigated clays was calculated using the same approach as the permeability of the previously indicated supports The acquired findings are shown in Figure 3b The various domains of application of membranes ultrafiltration microfiltration and nanofiltration have been characterized in the literature based on permeability to distilled water and appliedpressurevalue intervals 3747 In this regard the values obtained for the Lp permeability of different membranes in Figure 3b indicate that the membranes based on bentonite and Aomar clays are ultrafiltra tion membranes with values of Lp 7169 and 1512 Lm2hbar respectively and the mem Minerals 2023 13 273 11 of 19 brane based on kaolin is a microfiltration membrane with a value of Lp 54737 Lm2hbar The comparison of our findings with prior studies on natural zeolitebased ceramic mem branes highlights the application of these membranes for ultrafiltration and nanofiltra tion 354448 These studies have demonstrated their efficacy in filtering saline water and retaining monovalent and bivalent metals 35 The Study of the Efficiency of Our Membranes in the Filtration of a Local Effluent Our filtering membranes are specifically aimed at filtration of a localcheese effluent This is because the effluent needs to undergo special treatment to reduce its organic and inorganic contaminant levels prior to being released into the environment 4749 Figure 4 shows the difference in appearance of the effluent before and after filtration with varying transmembrane pressures on the developed membranes as well as the liquid in the feed tank The images reveal that before filtration the effluent has a white tint with high turbidity However after filtration through the microfiltration and ultrafiltration membranes at various pressures the resulting permeate is clear and transparent indicating the effectiveness of the membraned in clarifying the effluent The dark color and high turbidity of the liquid in the feed tank also supports this result Minerals 2022 12 x FOR PEER REVIEW 10 of 17 Figure 4 Representative image of the visual appearance of the effluent a before filtration on the developed membranes b after filtration on the developed membrane based on bentonite c after filtration on the developed membrane based on Aomar clay and d after filtration on the developed membrane based on kaolin Tables 46 shows the results of physicochemicalpollutantparameter analyses per formed on our samples before and after membrane filtration Table 4 Results of the physicochemical pollution parameters measured on the studied effluent using membrane based on bentonite UF Membrane Parameter of Pollution Measured Effluent before Filtration Permeate Collected at 1 bars Permeate Collected at 2 bars Permeate Collected at 3 bars Permeate Collected at 4 bars Effluent Re tained in the Feed Tank Membrane based on Bentonite UF Turbidity NTU 2400 108 105 102 122 2812 Conductivity µS 2170 773 762 753 758 632 Ammonium NH4 mgL 592 305 191 138 232 4724 Nitrites NO2 mgL 288 084 056 048 116 2212 Nitrates NO3 mgL 768 975 78 549 105 4815 Phosphates PO43 mgL 297 1002 460 233 082 27423 pH 680 690 705 708 712 638 Figure 4 Representative image of the visual appearance of the effluent a before filtration on the developed membranes b after filtration on the developed membrane based on bentonite c after filtration on the developed membrane based on Aomar clay and d after filtration on the developed membrane based on kaolin Tables 46 shows the results of physicochemicalpollutantparameter analyses per formed on our samples before and after membrane filtration Minerals 2023 13 273 12 of 19 Table 4 Results of the physicochemical pollution parameters measured on the studied effluent using membrane based on bentonite UF Membrane Parameter of Pollution Measured Effluent before Filtration Permeate Collected at 1 bars Permeate Collected at 2 bars Permeate Collected at 3 bars Permeate Collected at 4 bars Effluent Retained in the Feed Tank Membrane based on Bentonite UF Turbidity NTU 2400 108 105 102 122 2812 Conductivity µS 2170 773 762 753 758 632 Ammonium NH4 mgL 592 305 191 138 232 4724 Nitrites NO2 mgL 288 084 056 048 116 2212 Nitrates NO3 mgL 768 975 78 549 105 4815 Phosphates PO43 mgL 297 1002 460 233 082 27423 pH 680 690 705 708 712 638 Temperature C 217 208 215 217 235 234 COD mgL 5920 66551 64012 54032 4768 167665 BOD5 mgL 2400 81228 75723 67145 57578 83035 RATIO CODBOD 5 247 082 085 080 083 202 Table 5 Results of the physicochemicalpollution parameters measured on the studied effluent using membrane based on Aomar clay UF Membrane Parameter of Pollution Measured Effluent before Filtration Permeate Collected at 1 bars Permeate Collected at 2 bars Permeate Collected at 3 bars Permeate Collected at 4 bars Effluent Retained in the Feed Tank Membrane based on Aomar clay UF Turbidity NTU 2400 106 874 24 260 2700 Conductivity µS 2170 1668 1628 1613 1618 1347 Ammonium NH4 mgL 592 52 402 281 458 3985 Nitrites NO2 mgL 288 195 12 095 24 176 Nitrates NO3 mgL 768 217 152 12 22 238 Phosphates PO43 mgL 297 144 1007 492 157 25888 pH 680 692 703 705 707 635 Temperature C 217 215 223 229 237 239 COD mgL 5920 1520 1476 1254 1123 359523 BOD5 mgL 2400 1740 1650 1440 1254 176642 RATIO CODBOD 5 396 087 089 087 089 204 Minerals 2023 13 273 13 of 19 Table 6 Results of the physicochemical pollution parameters measured on the studied effluent using membrane based on kaolin MF Membrane Parameter of Pollution Measured Effluent before Filtration Permeate Collected at 1 bars Permeate Collected at 2 bars Permeate Collected at 3 bars Permeate Collected at 4 bars Effluent Retained in the Feed Tank Membrane based on Kaolin MF Turbidity NTU 2400 28 19 14 16 2650 Conductivity µS 2170 2023 2003 1985 1993 1499 Ammonium NH4 mgL 592 188 1285 965 1095 546 Nitrites NO2 mgL 288 112 16 144 277 1554 Nitrates NO3 mgL 768 2672 184 1432 85 64 Phosphates PO43 mgL 297 1176 79 432 325 2153 pH 680 690 695 700 73 632 Temperature C 214 217 215 216 225 21 COD mgL 5920 1320 1020 950 798 352054 BOD5 mgL 2400 1400 1379 1136 936 1550 RATIO CODBOD 5 246 094 078 084 084 227 Minerals 2023 13 273 14 of 19 The turbidity level of the examined effluent before filtering was 2400 NTU which is substantially higher than the recommended limit in Algeria 80 NTU The rise in turbidity might be attributed to the mobilization of organic and inorganic particles in suspension 50 The turbidity in the permeate collected at different pressures was reduced to values well below the required standard after filtration in contrast to the highest turbidity ob served in the liquid retained in the feed tank this result indicates that the suspended matter was retained by the three membranes studied These findings are consistent with previous studies on the measuring of turbidity before and after membrane filtration 374551 A reduction in turbidity has been observed with the rise of transmembrane pressure up to 3 bars after which they progressively increase as indicated in Tables 46 which may be explained by a partial fouling of the membranes caused by transmembrane pressures of more than 3 bars 52 351 Conductivity The recorded electricalconductivity values from both the effluent before filtration and the permeates after filtration at various transmembrane pressures between 1 and 4 bars are better than the Algerian standard cited in Table 2 These findings explain why the samples studied had substantial salt even after mem brane filtration less than 2500 µScm This salinity is caused by salts washing chemicals detergents and disinfectants 5354 It is critical to note here that the values of electrical conductivity steadily rise as the transmembrane pressure reaches 3 bars which corresponds to the turbidity values reached beyond 3 bars These conductivity findings in Tables 46 suggest that ultrafiltration membranes are more effective than microfiltration membranes for mineralsalt retention as reported in the literature 51 This result of the successful retention of mineral salts by our two ultrafiltration membranes is in line with previous research findings on the filtration of saline water using ceramic membranes based on natural zeolites 354448 352 Ammonium NH4 Ammonia nitrogen is a reliable indication of urbaneffluent contamination in water systems The findings in Tables 46 reveal that the quantity of NH4 ions in the unfiltered effluent is excessively high reaching 592 mgL After ultrafiltration and microfiltration by the membrane at various pressures a considerable drop in the quantity of these ions was noticed which was followed by an increase in the retained liquid showing that these ions were successfully retained by filtration on all three membranes Indeed better values for NH4 ions were found After ultrafiltration with the bentonite and Aomar clay membranes the result was consistent with the necessary standardlimit value 5 mgL even when the applied pressure was increased from 1 to 4 bars However the amount of NH4 produced via mem brane microfiltration based on kaolin is substantially greater than the Algerian standard This outcome is due to the excessively high permeability achieved by the kaolinbased membrane at 54737 Lm2hbar see Figure 3b which is approximately four times greater than the permeability values of the bentonite and Aomarclaybased membranes This explains why the porosity of the kaolinbased membrane is significant allowing a great amount of ammonium ions to pass through its pores even at low transmembrane pressure refer to the results in Table 6 of the revised version of the manuscript 353 Nitrates NO3 and Nitrite NO2 Nitrates and nitrites are both oxidized forms of nitrogen pollution found in wastewa ter 55 The presence of lactating proteins mineral nitrogen in milk the bacterial oxidation of ammonia andor organicmatter decomposition and the usage of nitric acid during washing all contribute to the high concentration of these ions that define nitrogen pollu tion 53 Tables 46 shows that the measured nitrate and nitrite levels in the unfiltered Minerals 2023 13 273 15 of 19 effluent are much higher than the necessary requirements 30 mgL for NO3 ions and 03 mgL for NO2 ions Even at high transmembrane pressures we detect a drop in these values after filtration on our UF and MF membranes Indeed the amounts of NO3 recovered after filtering are less than the acceptable requirements allowing us to conclude that these ions were partly retained by the two filtration procedures in all membranes tested Moreover the concentration of NO2 ions obtained after filtering using the two procedures of UF and MF is lower than the necessary standard This conclusion is explained by the fact that NO2 is an intermediate molecule that is unstable in the presence of oxygen and has a lower concentration than the two other forms namely nitrate and ammonium ions 56 354 Phosphates PO43 The amount of ions in orthophosphates obtained in Tables 46 for the unfiltered efflu ent is higher than the Algerian standard 10 mgL which is most likely due to the usage of H3PO4 for machine cleaning at the level of cheese manufacturers in general Further more phosphorus compounds such as soluble orthophosphates and organophosphorus derivatives may be found in natural waters and wastewater 55 The number of orthophosphate Ions Is lowered below the acceptable level after filtering using ultrafiltration membranes based on bentonite and Aomar clays regardless of the applied transmembrane pressure 14 bars However the quantities of these ions following filtration on kaolinbased microfiltration membranes remain too high at all pressures employed These findings suggest that a membraneultrafiltration method can achieve orthophosphate retention but not a microfiltration procedure 355 pH and Temperature pH is an effective indication of pollution it fluctuates depending on whether the effluent is basic or acidic The biological pH range is 65 to 85 57 Indeed the pH values obtained before and after filtration for the three kinds of membranes demonstrate that all of the samples studied had pH values between 68 and 73 These results are consistent with those of the rejected effluents in Algeria where the pH must be in the range 6585 Temperature changes have a significant impact on the formation of microorganism colonies 5859 Indeed increasing the temperature of industrial effluents promotes their growth and hence the consumption of huge amounts of oxygen while decreasing the amount of dissolved oxygen in these effluents 60 According to Tables 46 the observed temperatures for all ultrafiltration and microfiltration membrane samples are almost consistent and fall below the acceptable limit 30 C This result indicates that the examined samples do not constitute a thermalpollution concern to the receiving natural environment Values over 30 C on the other hand contribute to the acceleration of biological processes for the treatment of industrial effluents by increasing the kinetics of organic degrading matter 61 356 The Chemical Oxygen Demand COD The COD data Tables 46 demonstrate that the unfiltered effluent is highly con taminated with organic matter with a value of 5928 mgL which is much more than the necessary limit 120 mgL The COD value reported in this unfiltered effluent is three times that found in study work on wastewaterCOD analysis 62 This conclusion may be explained by the fact that cheese effluents include residues of milk and chemical products used for machine cleaning at the cheesefactory level resulting in an increase in the quantity of organic matter responsible for the growth of aerobic bacteria 63 After filtering at pressures ranging from 1 to 4 bars the COD value drops to between 6655 and 4768 mgL approximately 90 of organic matter eliminated for the bentonite membrane between 1520 and 1123 mgL approximately 81 of organic matter eliminated for the Aomarclay membrane and between 1320 and 798 mgL approximately 90 of organic matter eliminated for the kaolin membrane These values remain high following Minerals 2023 13 273 16 of 19 filtering by the two UF and MF procedures indicating that the organic components in this cheese effluent were partly retained by all of the membranes tested The results of our investigation of the COD show improved outcomes compared to previous research on the filtration of dairy effluent conducted over a onemonth period at a sequencingbatch reactor station 6 Our results are even more favorable in comparison to the treatment of wastewater in a series of three microphytelagoon basins 63 357 BOD5 Biological Oxygen Demand for 5 days The findings in Tables 46 further demonstrate that the BOD5 value obtained for the effluent before filtering is extremely high 2400 mgL which explains why this effluent is so rich in biodegradable compounds After filtering the BOD5 in all permeates sampled at each applied pressure from 1 to 4 bars falls progressively across all membranes examined This gradual drop when pressure is increased may be explained by the partial fouling of our membranes over time It is critical to note that all BOD5 readings measured before and after filtering remain very high and exceed the necessary level of 35 mgL 358 The Ratio of CODBOD5 The CODBOD5 ratio allows us to assess the biodegradability of contaminants and determine the purification chain of a given effluent Wastewater rejected directly into receiving waters exhibits householdwastewater characteristics CODBOD5 3 64 This increasing ratio suggests an increase in nonbiodegradable organic matter 5759 The CODBOD5 ratio values obtained in Tables 46 for the permeate collected after filtering of our effluent on the three membranes investigated at varying pressures are significantly lower than 3 between 074 and 094 indicating that these are readily biodegradable effluents 61 The CODBOD5 ratios of the effluent before filtering and the liquid retained in the feed tank on the other hand are between 2 and 3 indicating that they are moderately biodegradable effluents 575961 indeed as stated by Mesrouk et al 60 and Litébé et al 65 an analysis of this ratio clearly highlights the biodegradability of wastewater These findings indicate that all of our samples both before and after membrane filtration may be purified using biological treatment 5861 4 Conclusions In the study conducted here tubular supports were fabricated using three clays sourced from various regions in Algeria with the intention of utilizing them in ultrafiltra tion and microfiltration processes Results showed that the kaolinbased support had the highest water permeability The developed membranes effectively clarified a localcheese effluent and retained suspended particles and organic compounds at transmembrane pres sures less than or equal to 3 bars The ultrafiltration membranes based on bentonite and Aomar clay retained NH4 ions but this was not the case for the microfiltration based on kaolin unlike the NO2 and NO3 ions which all three membranes tested retained The study found that when the transmembrane pressure is greater than 3 bars NH4 and NO2 ions begin to cross the membranes and their retention is facilitated by ultrafiltration membranes based on bentonite and Aomar clay The analysis showed that the permeates collected at pressures between 1 and 4 bars are readily biodegradable and require bio logical treatment The study concluded that COD and BOD5 are important for reducing organic matter and biodegradablematerial loads and that the permeates collected are fairly biodegradable and need biological treatment Author Contributions Conceptualization LH and DEA methodology LH DEA and AH validation LM and AA formal analysis LH and DEA investigation LH resources LM and AA data curation LH and DEA writingoriginal draft preparation LH writingreview and editing AH LM and AA visualization LM and AA supervision LM and AA project admin istration LM and AA All authors have read and agreed to the published version of the manuscript Funding This research received no external funding Minerals 2023 13 273 17 of 19 Institutional Review Board Statement Not applicable Informed Consent Statement Not applicable Data Availability Statement Not applicable Acknowledgments The authors wish to thank all who assisted in conducting this work Conflicts of Interest The authors declare no conflict of interest References 1 Mustapha S Shuaib DT Ndamitso MM Etsuyankpa MB Sumaila A Mohammed UM Nasirudeen MB Adsorption isotherm kinetic and thermodynamic studies for the removal of PbII CdII ZnII and CuII ions from aqueous solutions using Albizia lebbeck pods Appl Water Sci 2019 9 142 CrossRef 2 Mustapha S Dauda B Ndamitso M Mathew J Bassey U Muhammed S Biosorption of Copper from Aqueous Solutions by Raw and Activated Spines of Bombax Buonopozense Equilibrium Kinetics and Thermodynamic Studies Int J Appl Chem 2014 4 887903 CrossRef 3 Crini G Torri G Lichtfouse E Kyzas GZ Wilson LD MorinCrini N Dye Removal by Biosorption Using CrossLinked ChitosanBased Hydrogels Environ Chem Lett 2019 17 16451666 CrossRef 4 Sarkar B Chakrabarti P Vijaykumar A Kale V Wastewater Treatment in Dairy IndustriesPossibility of Reuse Desalination 2006 195 141152 CrossRef 5 Sanja P Dragiˇcevic T Hren M The Improvement of Dairy Wastewater Treatment Efficiency By the Addition of Bioactivator Mljekarstvo 2010 60 198206 6 El Ghammat A Riffi K Zerrouk M A Study of the Performance of a Sequential Bioreactor Plant for the Treatment of Dairy Effluents LARHYSS J 2019 37 721 7 Saheed M Dauda BEN Iyaka Y Tsado MJ Aliyu A Shaba EY Removal of Heavy Metals from Aqueous Solutions by Modified Activated Carbon from Bombax Buonopozense Int J Eng Sci 2014 3 1724 8 Zamouche M Tahraoui H Laggoun Z Mechati S Chemchmi R Kanjal MI Amrane A Hadadi A Mouni L Optimization and Prediction of Stability of Emulsified Liquid Membrane ELM Artificial Neural Network Processes 2023 11 364 CrossRef 9 Mouni L Belkhiri L Bollinger JC Bouzaza A Assadi A Tirri A Dahmoune F Madani K Remini H Removal of Methylene Blue from Aqueous Solutions by Adsorption on Kaolin Kinetic and Equilibrium Studies Appl Clay Sci 2018 153 3845 CrossRef 10 Imessaoudene A Cheikh S Bollinger JC Belkhiri L Tiri A Bouzaza A El Jery A Assadi A Amrane A Mouni L Zeolite Waste Characterization and Use as LowCost Ecofriendly and Sustainable Material for Malachite Green and Methylene Blue Dyes Removal BoxBehnken Design Kinetics and Thermodynamics Appl Sci 2022 12 7587 CrossRef 11 Imessaoudene A Cheikh S Hadadi A Hamri N Bollinger JC Amrane A Tahraoui H Manseri A Mouni L Adsorption Performance of Zeolite for the Removal of Congo Red Dye Factorial Design Experiments Kinetic and Equilibrium Studies Separations 2023 10 57 CrossRef 12 Farch S Yahoum MM Toumi S Tahraoui H Lefnaoui S Kebir M Zamouche M Amrane A Zhang J Hadadi A et al Application of Walnut Shell Biowaste as an Inexpensive Adsorbent for Methylene Blue Dye Isotherms Kinetics Thermodynamics and Modeling Separations 2023 10 60 CrossRef 13 Hadadi A Imessaoudene A Bollinger JC Assadi AA Amrane A Mouni L Comparison of Four PlantBased Bio Coagulants Performances against Alum and Ferric Chloride in the Turbidity Improvement of Bentonite Synthetic Water Water 2022 14 3324 CrossRef 14 Hadadi A Imessaoudene A Bollinger JC Cheikh S Assadi AA Amrane A Kebir M Mouni L Parametrical Study for the Effective Removal of Mordant Black 11 from Synthetic Solutions Moringa Oleifera Seeds Extracts Versus Alum Water 2022 14 4109 CrossRef 15 Hadadi A Imessaoudene A Bollinger JC Bouzaza A Amrane A Tahraoui H Mouni L Aleppo Pine Seeds Pinus Halepensis Mill as a Promising Novel Green Coagulant for the Removal of Congo Red Dye Optimization via Machine Learning Algorithm J Environ Manag 2023 331 117286 CrossRef PubMed 16 Tahraoui H Belhadj AE Triki Z Boudella N Seder S Amrane A Zhang J Moula N Tifoura A Ferhat R et al Mixed CoagulantFlocculant Optimization for Pharmaceutical Effluent Pretreatment Using Response Surface Methodology and Gaussian Process Regression Process Saf Environ Prot 2023 169 909927 CrossRef 17 Cheikh S Imessaoudene A Bollinger JC Hadadi A Amar M Bouzaza A Assadi AA Amrane A Zamouche M El Jery A et al Complete Elimination of the Ciprofloxacin Antibiotic from Water by the Combination of Adsorption Photocatalysis Process Using Natural Hydroxyapatite and TiO2 Catalysts 2023 13 336 CrossRef 18 Joshiba J Senthil Kumar P Carolin F Jayashree E Ramamurthy R Sivanesan S Critical Review on Biological Treatment Strategies of Dairy Wastewater Desalination Water Treat 2019 160 94109 CrossRef 19 Ang WL Mohammed A Johnson D Hilal N Forward Osmosis Research Trends in Desalination and Wastewater Treatment A Review of Research Trends Over the Past Decade J Water Process Eng 2019 31 100886 CrossRef Minerals 2023 13 273 18 of 19 20 Hube S Eskafi M Hrafnkelsdóttir K Bjarnadóttir B Bjarnadóttir M Axelsdóttir S Wu B Direct Membrane Filtration for Wastewater Treatment and Resource Recovery A Review Sci Total Environ 2020 710 136375 CrossRef 21 Ejraei A Aroon M Ziarati A Wastewater Treatment Using a Hybrid System Combining Adsorption Photocatalytic Degrada tion and Membrane Filtration Processes J Water Process Eng 2019 28 4553 CrossRef 22 Goswami KP Pugazhenthi G Credibility of Polymeric and Ceramic Membrane Filtration in the Removal of Bacteria and Virus from Water A Review J Environ Manag 2020 268 110583 CrossRef PubMed 23 Khouni I Louhichi G Ghrabi A MOULIN P Efficiency of a CoagulationFlocculationMembrane Filtration Hybrid Process for the Treatment of Vegetable Oil Refinery Wastewater for Safe Reuse and Recovery Process Saf Environ Prot 2020 135 323341 CrossRef 24 Shrestha R Ban S Devkota S Sharma S Joshi R Tiwari AP Kim HY Joshi MK Technological trends in heavy metals removal from industrial wastewater A review J Environ Chem Eng 2021 9 105688 CrossRef 25 Vieira W Farias M Spaolonzi M Silva M Vieira M Removal of Endocrine Disruptors in Waters by Adsorption Membrane Filtration and Biodegradation A Review Environ Chem Lett 2020 18 11131143 CrossRef 26 Alfonso P SernaGalvis E Bussemaker M TorresPalma R Lee J A Review on Pharmaceuticals Removal from Waters by Single and Combined Biological Membrane Filtration and Ultrasound Systems Ultrason Sonochem 2021 76 105656 CrossRef 27 Fitobór K Quant B Is the Microfiltration Process Suitable as a Method of Removing Suspended Solids from Rainwater Resources 2021 10 21 CrossRef 28 Jinlong W Tang X Liu Y Xie B Li G Liang H SelfSustained Ultrafiltration Coupling Vermifiltration for Decentralized Domestic Wastewater Treatment Microbial Community and Mechanism Resour Conserv Recycl 2022 177 106008 CrossRef 29 Bakhta M Abderahmane D Djafer L MarinAyral RM Ayral A Wastewater Treatment Using a Hybrid Process Coupling Adsorptionon Marl and Microfiltration Membr Water Treat 2020 11 111 30 Rani S Kumar R Insights on Applications of LowCost Ceramic Membranes in Wastewater Treatment A MiniReview Case Stud Chem Environ Eng 2021 4 100149 CrossRef 31 Asif MB Zhang Z Ceramic Membrane Technology for Water and Wastewater Treatment A Critical Review of Performance FullScale Applications Membrane Fouling and Prospects Chem Eng J 2021 418 129481 CrossRef 32 Samadi A Gao L Kong L Orooji Y Zhao S WasteDerived LowCost Ceramic Membranes for Water Treatment Opportuni ties Challenges and Future Directions Resour Conserv Recycl 2022 185 106497 CrossRef 33 Dong B Wang FH Yang MY Yu JL Hao LY Xu X Wang G Agathopoulos S PolymerDerived Porous SiOC Ceramic Membranes for Efficient OilWater Separation and Membrane Distillation J Membr Sci 2019 579 111119 CrossRef 34 Abdullayev A Bekheet M Hanaor D Gurlo A Materials and Applications for LowCost Ceramic Membranes Membranes 2019 9 105 CrossRef 35 Aloulou W Aloulou H Khemakhem M Duplay J Daramola MO Amar R Synthesis and Characterization of ClayBased Ultrafiltration Membranes Supported on Natural Zeolite for Removal of Heavy Metals from Wastewater Environ Technol Innov 2020 18 100794 CrossRef 36 Iaich S Lahcen M Development and Characterization of Inorganic Membranes for MicroFiltration Deposited on Tubular Supports Ceramic Based on Natural Moroccan Clay J Mater Environ Sci 2014 5 18081815 37 Khemakhem M Khemakhem S Ayedi S Amar R Study of Ceramic Ultrafiltration Membrane Support Based on Phosphate Industry Subproduct Application for the Cuttlefish Conditioning Effluents Treatment Ceram Int 2011 37 36173625 CrossRef 38 Boudaira B Harabi A Bouzerara F Zenikheri F Foughali L Guechi A Preparation and characterization of membrane supports for microfiltration and ultrafiltration using kaolin DD2 and CaCO3 Desalination Water Treat 2015 57 52585265 CrossRef 39 Harabi A Bouzerara F Fabrication of Tubular Membrane Supports from Low Price Raw Materials Using Both Centrifugal Casting andor Extrusion Methods INTECH Open Access Publisher London UK 2011 ISBN 9789533076249 40 Jafari B Abbasi M Hashemifard S Sillanpää M Elaboration and Characterization of Novel TwoLayer Tubular Ceramic Membranes by Coating Natural Zeolite and Activated Carbon on MulliteAluminaZeolite Support Application for Oily Wastewater Treatment J Asian Ceram Soc 2020 8 848861 CrossRef 41 Arzate A Procédés de Séparation Membranaire et Leur Application Dans lindustrie AlimentaireRevue de Littérature Entre de Recherche de Développement et de Transfert Technologique Acéricole Quebec QC Canada 2008 42 Yang G Tsai CM Effects of Starch Addition on Characteristics of Tubular Porous Ceramic Membrane Substrates Desalination 2008 233 129136 CrossRef 43 Bouzerara F Harabi A Achour S Larbot A Porous Ceramic Supports for Membranes Prepared from Kaolin and Doloma Mixtures J Eur Ceram Soc 2006 26 16631671 CrossRef 44 Zhu B Morris G Moon I Gray S Duke M Diffusion Behaviour of Multivalent Ions at Low PH through a MFIType Zeolite Membrane Desalination 2018 440 8898 CrossRef 45 Harabi A Guechi A Condom S Production of Supports and Filtration Membranes from Algerian Kaolin and Limestone Procedia Eng 2012 33 220224 CrossRef 46 Jedidi I Khemakhem S Saidi S Larbot A ElloumiAmmar N Fourati A Charfi A Abdelhamid BS Amar R Preparation of a New Ceramic Microfiltration Membrane from Mineral Coal Fly Ash Application to the Treatment of the Textile Dying Effluents Powder Technol 2011 208 427432 CrossRef Minerals 2023 13 273 19 of 19 47 Daufin G Aimar P Séparations Par Membrane Dans lindustrie Alimentaire Techniques Ingénieur Saintdenis France 2004 48 Mulyati S Arahman N Muchtar S Yusuf M Removal of Metal Iron from Groundwater Using Aceh Natural Zeolite and Membrane Filtration IOP Conf Ser Mater Sci Eng 2017 180 012128 CrossRef 49 Majouli A Tahiri S Younssi S Loukili H Albizane AA Elaboration of New Tubular Ceramic Membrane from Local Moroccan Perlite for Microfiltration Process Application to Treatment of Industrial Wastewaters Ceram Int 2012 38 42954303 CrossRef 50 Mustapha s Ndamitso M Mohammed UM Adeosun NO Idris M Study on Activated from Melon Citrullus lanatus Husk as Natural Adsorbent for Removal of Hardness in Water Adv Anal Chem 2016 6 19 51 Demirel B Yenigün O Onay T Anaerobic Treatment of Dairy Wastewaters A Review Process Biochem 2005 40 25832595 CrossRef 52 Crini G Montiel AJ Badot PM Traitement et Épuration Des Eaux Industrielles Polluées Procédés Membranaires Bioadsorption et Oxydation Chimique Presses Universitaires de FrancheComté Besançon France 2007 ISBN 2848671971 53 Mouiya M Abourriche A Bouazizi A Benhammou A El Hafiane Y Abouliatim Y Nibou L Oumam MM Ouammou M Smith A et al Flat Ceramic Microfiltration Membrane Based on Natural Clay and Moroccan Phosphate for Desalination and Industrial Wastewater Treatment Desalination 2018 427 4250 CrossRef 54 Hamdani A Ahmed M Mountadar M Assobhei O Évolution de La Qualité PhysicoChimique et Bactériologique dun Effluent Laitier Sur Un Cycle Annuel Déchets Sci Tech 2005 8009 CrossRef 55 Akil A Hassan T Lahcen B Abderrahim L Etude de La Qualité PhysicoChimique et Contamination Métallique Des Eaux de Surface Du Bassin Versant de Guigou Maroc Eur Sci J 2014 10 8494 56 Cardot C Les Traitements de leau Procédés PhysicoChimiques et Biologiques Ellipses Paris France 2010 ISBN 2729861874 57 Belghyti D El Guamri Y Ztit G Ouahidi M Joti M Harchrass A Amghar H Bouchouata O El Kharrim K Bounouira H Caractérisation PhysicoChimique Des Eaux Usées dabattoir En Vue de La Mise En Œuvre dun Traitement Adéquat Cas de Kénitra Au Maroc Afr Sci Rev Int Sci Technol 2009 5 5 CrossRef 58 Maiga A Konate Y Wethe J Denyigba K Zoungrana D Togola L Performances Épuratoires dune Filière de Trois Étages de Bassins de Lagunage à Microphytes Sous Climat Sahélien Cas de La Station de Traitement Des Eaux Usées de lEIER Sud Sci Technol 2006 14 412 59 Fathallah Z Elkharrim K Fathallah R Hbaiz E Hamid C Ayyach A Elkhadmaoui A Belghyti D Etude Physico Chimique Des Eaux Usées de lunité Industrielle Papetière CDM a Sidi Yahia El Gharb Maroc LARHYSS J 2014 60 Mesrouk H Hadj Mahammed M Touil Y Amrane A PhysicoChemical Characterization of Industrial Effluents from the Town of Ouargla South East Algeria Energy Procedia 2014 50 255262 CrossRef 61 Youssef E Nahli A Chlaida M Kamal C Contribution A La Caractérisation PhysicoChimique Des Effluents De La Cosumar Casablanca Maroc En Vue De Leur Traitement Approprié Eur Sci J 2018 14 212 CrossRef 62 Gnagne Y Yapo B Meite L Kouame V Gadji A Mambo V Houenou P Caractérisation PhysicoChimique et Bactériologique Des Eaux Usées Brutes Du Réseau dégout de La Ville dAbidjan Int J Biol Chem Sci 2015 9 1082 CrossRef 63 Mustapha S Oladejo TJ Muhammed NM Saka AA Oluwabunmi AA Abdulkabir M Joel OO Fabrication of Porous Ceramic Pot Filters for Adsorptive Removal of Pollutants in Tannery Wastewater Sci Afr 2021 11 e00705 CrossRef 64 Zegaoula W Khellaf N Evaluation Du Degré de Pollution Des Rejets Liquides et Atmosphériques Du Complexe FertialAnnaba Algérie LARHYSS J 2014 65 Litébé A NgakegniLimbili A Mvouezolo R Nkounkou Loumpangou C Nzobadila D Ouamba J Impact of Reject of Dairy Wastewater into the Aquatic Environment Case of the Bayo Dairy Company BrazzavilleCongo Int J Environ Clim Chang 2020 112 CrossRef DisclaimerPublishers Note The statements opinions and data contained in all publications are solely those of the individual authors and contributors and not of MDPI andor the editors MDPI andor the editors disclaim responsibility for any injury to people or property resulting from any ideas methods instructions or products referred to in the content IOP Conference Series Materials Science and Engineering PAPER OPEN ACCESS Development of Ceramic Membrane Combination Process in the Treatment of Industrial Wastewater in China To cite this article Yue Wang et al 2018 IOP Conf Ser Mater Sci Eng 392 022039 View the article online for updates and enhancements You may also like Application Prospect of Ceramic Membrane Coupling Process in Refinery Wastewater R Z Cheng L P Qiu G C Liu et al Purification of fluid catalytic cracking slurry oil at room temperature using ceramic membrane Changye Han Yongde Luo Kun Li et al Ceramic Membrane Coupling Process for Advanced Treatment of Electroplating Wastewater Qi Han Li ping Qiu Ren zhen Cheng et al This content was downloaded from IP address 17773101248 on 22112023 at 1010 1 Content from this work may be used under the terms of the Creative Commons Attribution 30 licence Any further distribution of this work must maintain attribution to the authors and the title of the work journal citation and DOI Published under licence by IOP Publishing Ltd 1234567890 MTMCE IOP Publishing IOP Conf Series Materials Science and Engineering 392 2018 022039 doi1010881757899X3922022039 Development of Ceramic Membrane Combination Process in the Treatment of Industrial Wastewater in China Yue Wang1 Liping Qiu1 Qi Qiu1 2 1School of Civil Engineering and Architecture University of Jinan 336 Nanxinzhuang West Road Jinan 250022 China 2School of Environmental and Municipal Engineering Lanzhou Jiaotong University 88 Anning West Road Lanzhou 730070 China Corresponding authors email lipingqiu163com Abstract Due to the advantages of ceramic membrane such as high separation efficiency easy operation good chemical stability and low energy consumption it has an expansive application prospect in the field of industrial wastewater treatment However the ceramic membrane has a low removal effect to the contaminants whose molecular diameters are smaller than the membrane pores the poor water quality also aggravates the pollution and shortens the age of ceramic membrane Therefore it is significant to research the combination process of ceramic membrane This article summarizes the current ceramic membrane combination process in industrial wastewater treatment and describes their respective characteristics mechanism of reaction and removal effects Ultimately we would put forward the direction of the ceramic membrane combination process in the future 1 Introduction In recent years the emission of industrial wastewater in China was approximately 20 billion tons per year If wastewater is improperly treated the local ecological environment will be affected seriously The current methods for industrial wastewater treatment mainly include chemical methods physical methods physicalchemical methods and biological methods Although the chemical treatment technique is relatively mature the removal efficiency reduces significantly when the concentrations of pollutants are low The biological method has a long running time and it is unstable by the influence of seasonal change Because of the characteristics such as good chemical stability long operating cycle antipollution easy cleaning and regeneration nonpolar ceramic membranes is attracting increasing attention of related researchers Initially ceramic membrane had expensive price and small application range but the cost of membrane production has been gradually declining with the continuous improvement of membrane technology which is pushing the application of ceramic membranes 1 In reality if the ceramic membrane is used as one of the industrial wastewater treatment units we should reach the requirements of influent water quality otherwise the ceramic membrane will be easily contaminated and aged The combination of ceramic membrane and other processing units is contributed to the complementary advantages among the units Based on the research on ceramic membrane treatment of industrial wastewater in recent years this article would focus on the characteristics operating effects and related membrane fouling and aging of ceramic membrane combination process 2 1234567890 MTMCE IOP Publishing IOP Conf Series Materials Science and Engineering 392 2018 022039 doi1010881757899X3922022039 2 Ceramic membrane overlook 21 The mechanism and classification of ceramic membrane There are two mechanisms for the ceramic membranes to remove contaminants The first is the selfretaining action of membranes which can prevent particles larger than the membrane aperture from passing So the ceramic membrane can separate and purify pollutants The second is the adsorption capacity which can adsorb small molecular weight contaminants though chemical bonds van der Waals forces and electrostatic forces According to the pore size ceramic membrane can be divided into microfiltration membrane ultrafiltration membrane nanofiltration membrane and reverse osmosis membrane And the first three types of ceramic membranes are mainly applied in the industrial wastewater treatment 2 According to the shape which is determined by manufacturing technique and application field ceramic membrane can be divided into singlechannel tubular membrane multichannel tubular membrane flat membrane and hollow fiber membrane Among them the hollow fiber membrane is widely used in the water treatment field the tubular membrane has an abroad application in the solidliquid separation processes such as high solid phase content and landfill leachate and the flat membrane can be applied in the water resources field3 22 Technical advantages of ceramic membranes There are some inductions for the feature of ceramic membrane 221 Good chemical stability It is difficult for inorganic ceramic membrane to react with other substances and it has great resistance to oxidation and corrosion so it can operate normally under the conditions of strong acid and strong alkali 222 High mechanical strength Ceramic membrane can withstand high strength scouring and ceramic fibers are hardly damaged during operation thus the maintenance cost of ceramic membrane is low 223 Long lasting The ceramic membrane can be cleaned repeatedly which greatly prolongs the service life of ceramic membrane and reduces the operating cost of the treatment process 4 224 Good thermal stability The thermal resistance of ceramic membrane is great Most ceramic membranes can operate normally at the temperature below 800 some even reach 1000 so ceramic membrane can meet the temperature requirements of most industrial wastewater treatment 5 225 Low energy consumption Ceramic membrane can separate the contaminants at room temperature requiring membrane pressure without additional medicines Therefore the energy consumption of ceramic membrane is very low 3 Application of Ceramic Membrane and Its Combined Process of Industrial Wastewater Treatment 31 Coagulationceramic membrane combination process A lot of experiments showed that the quantity of pollution in water was reduced effectively and the removal efficiency of ceramic membrane was improved when coagulation process was used to be the pretreatment process6 After the combination process the water quality of the effluent was relatively stable 7 and the turbidity of effluent decreased below the national drinking water standard 8 The research of Yi Yanhong 10showed when the combination of coagulation and ceramic membrane microfiltration process was as the pretreatment of prebiochemical coking wastewater 3 1234567890 MTMCE IOP Publishing IOP Conf Series Materials Science and Engineering 392 2018 022039 doi1010881757899X3922022039 under optimal conditions the removal rates of turbidity color Degree oil content and CODcr were 95 80 90 and 81 respectively This study indicated the high efficiency and great compatibility of coagulationceramic membrane combination process and the process reduced the burden of the following treatment process 32 Ozone Ceramic Membrane Ultrafiltration Biological Activated Carbon Combination Process The research showed that ceramic membrane was difficult to remove soluble organic matter and ammonia nitrogen 11 thus it hindered the wide application of ceramic membrane Ozone can effectively reduce the molecular weight of pollutants in water and improve the biodegradability of wastewater but not affect the normal operation of ceramic membrane 12 At the same time bioactive carbon BAC can also reduce the concentration of organic and ammonia nitrogen in water 13 by adsorption so the combination of BAC ozone and ceramic membrane can prolong the service life of the ceramic membrane and reduce the concentration of the pollutants in the water Guo Jianning 14 and others found that the removal rate of ammonia nitrogen could be improved by increasing the DO concentration of inflow water And the appropriate DO concentration could reduce the ammonia nitrogen from 60 mgL to 05mgL or less By using ozone to degrade organic matter UV254 removal can be enhanced membrane flux can be increased by 25 to 30 and processing performance can be improved 33 The photocatalysisceramic membrane combination process photocatalysis Ceramic Membrane Reactor PMR which combines photocatalysis with ceramic membranes develops rapidly in China Due to the combination of two different processes this combination process has multiple advantages and makes up for certain defects which has a certain research value There are two different existing forms of photocatalyst floating and fixed The floating photocatalyst is put into the water for catalytic reaction and prevents from passing through ceramic membrane The fixed photocatalyst is fixed on the ceramic membrane and the photocatalytic reaction and membrane separation can simultaneously occur on the surface of ceramic membrane In fact the PMR reactor has very strict requirements on the membrane because the free radicals produced by the photocatalytic process may cause some damage to the membrane fibers and affect the normal operation of the membrane but the stability of the ceramic membrane is sufficient to avoid strong oxidizing free radicals and solve the problem of difficult recovery of photocatalyst 15 The contact area between the floating photocatalyst and the contaminants is larger than that between the fixed photocatalyst and the contaminants so the reaction of the floating photocatalyst is more complete 16 However when the floating photocatalyst is trapped by the ceramic membrane the ceramic membrane will have a certain degree of clogging resulting in a decrease in the flux of the film and therefore it is necessary to periodically backwash the ceramic film Although the fixed photocatalyst does not have the problem of reduced membrane flux it has a low catalytic efficiency 1718 and the related issues need to be further studied and examined 4 Conclusion In summary researchers pay more attention on ceramic membranes and their combination processes because of their high removal effect Besides when we treat different types of industrial wastewater such as petrochemical wastewater printing and dyeing wastewater and electroplating wastewater we should select the relevant combination process reasonably according to their unique water quality characteristic In order to accelerate the largescale application of ceramic membrane combination process it is necessary to consider the following advice 1 At present the ceramic membrane combination process has mainly existed in the laboratory test or trial operation stage so it is necessary to assess the difference between the actual wastewater 4 1234567890 MTMCE IOP Publishing IOP Conf Series Materials Science and Engineering 392 2018 022039 doi1010881757899X3922022039 treatment environment and the laboratory environment Currently we need a large number operational parameters of membrane combination process in industrial wastewater treatment to evaluate its feasibility and adjust the experimental conditions refer to the actual combination process operations 2 The ceramic membrane is more expensive than the organic membrane so many experts have some research on reducing the costs of membrane manufacture in the conditions of guaranteeing membrane performance such as finding cheap raw materials or additives simple manufacturing processes and so on Acknowledgement This work was financially supported by the National Science Foundation of China 51678276 the key research and development program of Shandong Province 2016CYJS07A033 2016GSF117012 2018GSF117026 and the Shandong Provincial Natural Science Foundation ZR2018BEE040 References 1 C Zhao M Zhou L and Cai Z 2016 Research progress of ceramic membrane and its combination process in drinking water treatment Water Waste Eng 52 13340 2 Geluwe S V Braeken L and Bruggen B V D 2011 Ozone oxidation for the alleviation of membrane fouling by natural organic matter A review Water Res 45 355170 3 Zhang C Fan Z Yang D Zhang J Meng F P and Wang L 2016 Technical advantages and market analysis of inorganic ceramic membranes Shandong Ceram 39 69 4 Cheng X X and Liang H 2016 The development and prospect of ceramic membrane drinking water treatment technology J Harbin Inst Technol 48 110 5 Zhang X S and Ni W H 2013 Current status and application of ceramic membrane development Environ Eng 31 10811 6 Zhu Y C 2011 Progress and application of commonly used ultrafiltration membrane combination process in drinking water treatment Water Purif Tech 30 7275 7 Li M Wu G and Guan Y 2011 Treatment of river water by a hybrid coagulation and ceramic membrane process Desalination 280 11419 8 Konieczny K Bodzek M and Rajca M 2006 A coagulationMF system for water treatment using ceramic membranes Desalination 198 9201 9 Shirasaki N Matsushita T and Matsui Y 2009 Comparison of removal performance of two surrogates for pathogenic waterborne viruses bacteriophage Qβ and MS2 in a coagulationceramic microfiltration system J Membr Sci 326 56471 10 ZHANG J DONG Q SUN Y X LIU X Q and MENG G Y 2006 Treatment of cathodic electrophoretic paint wastewater by coagulationceramic membrane microfiltration Membr Sci Tech 6 5760 11 Watanabe Y Kimura K and Suzuki T 1999 Membrane application to water purification process in Japan Development of hybrid membrane system Water Sci Technol 41 916 12 Schlichter B Mavrov V and Chmiel H 2003 Study of a hybrid process combining ozonation and membrane filtration filtration of model solutions Desalination 156 25765 13 Lee H C Jin Y P and Yoon D Y 2009 Advanced water treatment of high turbid source by hybrid module of ceramic microfiltration and activated carbon adsorption Effect of organicinorganic materials Korean J Chem Eng 26 69701 14 GUO J N ZHANG X H HU J Y WANG L Y ZHANG J G and Shen D Y 2013 Effect of Ozone Oxidation on the Reduction of Turbidity in Drinking Water by Ceramic Membrane Ultrafiltration Process J Environ Sci 33 968 75 15 Athanasekou C P Moustakas N G and MoralesTorres S 2014 Ceramic photocatalytic membranes for water filtration under UV and visible light Appl Catal B environ 178 1219 16 Romanos G E Athanasekou C P and Likodimos V 2013 Hybrid UltrafiltrationPhotocatalytic Membranes for Efficient Water Treatment Ind Eng Chem Res 52 1393847 5 1234567890 MTMCE IOP Publishing IOP Conf Series Materials Science and Engineering 392 2018 022039 doi1010881757899X3922022039 17 Kumakiri I Diplas S and Simon C 2011 Photocatalytic Membrane Contactors for Water Treatment Ind Eng Chem Res 50 600008 18 Ohno T 2004 Preparation of visible light active Sdoped TiO2 photocatalysts and their photocatalytic activities Water Sci 49 15962 Article Preparation of a ZirconiaBased Ceramic Membrane and Its Application for Drinking Water Treatment Mohamed Boussemghoune 1 Mustapha Chikhi 1 Fouzia Balaska 1 Yasin Ozay 2 Nadir Dizge 2 and Brahim Kebabi 3 1 Department of Environmental Engineering University Salah Boubnider Constantine 3 New City Ali Menjeli Constantine 25000 Algeria mustaphachikhiunivconstantine3dz MC fouziachikhiunivconstantine3dz FB 2 Department of Environmental Engineering Mersin University Mersin 33343 Turkey yozaymersinedutr YO ndizgemersinedutr ND 3 Chemical Department University Mentouri Constantine 1 Constantine 25000 Algeria brahimkebabiumcedudz Correspondence mohamedboussemghouneunivconstantine3dz Received 20 April 2020 Accepted 6 May 2020 Published 3 June 2020 Abstract This work concerns the preparation of a mineral membrane by the slip casting method based on zirconium oxide ZrO2 and kaolin The membrane support is produced from a mixture of clay kaolin and calcium carbonate calcite powders using heat treatment sintering Membrane and support characterization were performed by Scanning Electron Microscopy SEM Xray Fluorescence XRF Fourier Transform Infrared Spectroscopy FTIR Xray Diffraction XRD and Raman Spectroscopy The prepared mineral membrane was tested to treat drinking water obtained from different zones of the El Athmania Algeria water station raw coagulated decanted and bio filtered water Experimental parameters such as permeate flux turbidity and total coliforms were monitored The results showed that the mineral membrane was mainly composed of SiO2 and Al2O3 and the outer surface which represented the membrane support was much more porous than the inner surface where the membrane was deposited The permeate flux of the raw water decreased with filtration time due to a rejection of the organic matters contained in the raw water Moreover the absence of total coliforms in the filtrate and the increase in concentration in the concentrate indicate that the prepared mineral membrane can be used for drinking water treatment Keywords kaolin membrane ZrO2 flux turbidity total coliforms Symmetry 2020 12 933 2 of 15 which are currently underutilized 9 Kaolins are white friable and refractory clays consisting mainly of kaolinite of the formula Al2Si2O5OH4 or aluminum silicates Al2SiO5 It was discovered in China and it is used on the basis of porcelain manufacturing and also in the ceramic industry 10 Clay kaolin is used extensively for the production of microporous tubular supports that can withstand high pressures and chemical attacks where zirconium oxide gels are deposited for the preparation of membranes 11 Ceramic membranes CM have been used in various industries such as food petrochemical chemical biotechnological pharmaceutical dairy etc 12 So far many materials such as zeolites α and γ alumina Al2O3 titania TiO2 zirconia ZrO2 silicon oxide SiO2 and microporous glasses are commonly used in the development of ceramic membranes 1314 To date various methods have been used to prepare inorganic ceramic membranes These methods include chemical extraction the solgel method solid state sintering phase separation chemical vapor deposition and synthesis methods 1517 Zirconium oxide ZrO2 was used to prepare a flexible and thermally stable porous ceramic membrane using PVdFHFP as a binder The membrane showed 60 porosity with good electrolyte uptake thermal stability of up to 400 C and substantial Liion transport number 18 Ceramic zirconium membranes were used in the separation of oilinwater emulsion 1920 Commercial alumina microfiltration membranes were coated by the nanosized ZrO2 to reduce the membrane fouling by oil droplets They reported that the modified membrane reached the steady flux in a very short time and the steady flux retained 88 of the initial flux even when oil rejection was above 978 20 The oily wastewater produced from the posttreatment unit of the refinery processes was treated using flocculation and a zirconiabased microfiltration membrane 02 µm 21 The membrane was operated at a transmembrane pressure of 011 MPa and a crossflow velocity of 256 ms The membrane filtration results showed that the membrane fouling decreased and the permeate flux as well as the permeate quality increased with flocculation as pretreatment 21 In another study Kroll et al fabricated and characterized zirconia microtubes with 16 and 10 mm outer and inner diameters respectively for bacteria filtration and digestion 22 Tubular zirconia membranes sintered with a temperature of 1050 C had an open porosity of 513 with pore sizes of 02 µm and were suitable for bacteria filtration 22 Commercial tubular zirconia membranes supported on the alumina were used for modification with two different grafting procedures 23 Different kinds of hydrophobic ceramic membranes were prepared by grafting organosilane molecules FAS on the membrane surface The hydrophobic ceramic membranes with 200 and 50 nm pore diameters were used for water desalination by membrane distillation 24 The zirconia membrane was prepared using an in situ hydrothermal crystallization technique for the separation of methyl orange dye 25 The porosity average pore size and pure water permeability of the zirconia membrane were estimated to be 42 066 µm and 144 106 m3m2 s kPa respectively The prepared membrane showed a 61 rejection of methyl orange from the aqueous solution and a high permeation flux of 228 105 m3m2 s at 68 kPa operating pressure 25 The zirconiabased ceramic composite membranes were used for the separation of whey components 26 The prepared membrane enhanced relatively high protein content 80 and low lactose retention 7 with a 40 Lm2h permeate flux value A zirconia ultrafiltration UF membrane with a mean pore diameter of 40 nm was prepared in single step coating of zirconia nanopowder suspension by the slip casting method 27 The membrane was applied for treatment of industrial tannery and domestic kitchen sink wastewater They reported that 82 and 92 removal of chemical oxygen demand COD were obtained for tannery wastewater and kitchen sink wastewater respectively Turbidity was reduced below 1 NTU for both the effluents with complete removal of pathogenic organisms 27 In this study an inexpensive tubular zirconia membrane on a low cost porous ceramic support was synthesized and characterized Kaolin powders were used to prepare the membrane support CaCO3 and Methocel were used in the support preparation as inorganic and organic additives respectively The prepared ceramic membrane and support were characterized by SEM XRF FTIR Symmetry 2020 12 933 3 of 15 XRD and Raman Spectroscopy The membrane was used to remove organic matters from drinking water The developed ceramic membrane was also tested for removal of Escherichia coli E coli Variations in the permeate flux of distilled and raw drinking water versus filtration time were investigated Moreover the characterizations of raw drinking water permeate and concentrate quality were also illustrated 2 Material and Methods 21 Characterization of Raw Kaolin Powders Table 1 shows the chemical composition of the raw kaolin determined by Xray fluorescence XRF analysis A chemical composition of kaolin powders for the ceramic membrane support showed that SiO2 Al2O3 Fe2O3 were major elements However K2O Na2O MgO P2O5 TiO2 and MnO were detected as minor elements Table 1 Chemical analysis wt of the raw kaolin Oxide Weight SiO2 55080 Al2O3 29041 Fe2O3 2813 K2O 1422 Na2O 0320 MgO 0172 CaO 0010 P2O5 0082 TiO2 0066 MnO 0014 Loss on ignition 10980 22 The Methods of the Membrane Support and Ceramic Membrane Preparation In this part we describe the methods of the membrane support from the clay powders kaolin and zirconiabased ceramic membrane preparations The clay consisted mainly of aluminum silicate Al2SiO5 intended for the manufacture of the tubular microporous support The method of tubular support preparation can be summarized in the following steps 2829 Thermal treatment of the clay material at a temperature of 400600 C for 30 min for the removal of water contained in kaolin dehydration and the combustion of organic matters Grinding of the clay material to obtain small particles Sieving of the small particles to obtain particles smaller than 125 µm Addition of kaolin 75 and calcium carbonate CaCO3 22 for the appearance of pores with an acceptable number and size in the final support Addition of an organic additive Methocel 3 to improve the elastic properties of the dough and to facilitate the formation process Mixing of the abovementioned materials with the presence of the solvent distilled water by using the mixer until a paste of good elastic properties was obtained Then the mixture was placed in a tightly closed plastic bag for 12 h to properly spread the water in the ceramic paste Extrusion of ceramic paste in tubular form Drying of the tubular support with ambient air by placing it on the machine containing the rotating cylinders to dry it uniformly and maintain its shape for 24 h Symmetry 2020 12 933 4 of 15 Sintering the components of the ceramic paste that forms the support at a temperature equal to 1100 C which will convert it to anorthite according to a series of reactions during a specific thermal program The sintering of the support was realized in the following steps First the temperature of the chamber was increased from the ambient temperature to the temperature of 250 C with a rise speed of 3 Cmin and a plateau of 15 min During this step water could be eliminated quickly Second the temperature was increased from 250 to 1100 C with a rise speed of 3 Cmin and a plateau of 60 min During this step organic matters could be removed Figure 1 Symmetry 2019 11 x FOR PEER REVIEW 4 of 16 The sintering of the support was realized in the following steps First the temperature of the chamber was increased from the ambient temperature to the temperature of 250 C with a rise speed of 3 Cmin and a plateau of 15 min During this step water could be eliminated quickly Second the temperature was increased from 250 to 1100 C with a rise speed of 3 Cmin and a plateau of 60 min During this step organic matters could be removed Figure 1 Figure 1 Thermal program used for the sintering of the support 23 The Method of the Slip Casting Membrane Preparation The method consisted of suspending zirconia and polyvinyl alcohol in distilled water and pouring the produced slip inside the porous support Figure 2 The method results in the controlled diffusion process which amounts to a simple loss of water from the suspension in the mass of the support this causes the accumulation of zirconia particles on its surface The support sintered with thermal sequences ensures that the material can withstand high pressures and chemical attacks However zircon oxide ZrO2 accumulated in the inner part of the tubular support provides the formation of selective permeable membrane The method of zirconiabased ceramic membrane preparation can be summarized in the following steps Take 70 of the distilled water and add in 4 by weight of ZrO2 powder to mix the mixture until a good homogeneous mixture was obtained Place the mixture in an ultrasonic bath for 10 min to dispel the granules and dissolve the sediments Then add 26 polyvinyl alcohol PVA and mix for 12 h to obtain the suspension solution The solution is poured into the support for 10 min and dried for 5 min Figure 1 Thermal program used for the sintering of the support 23 The Method of the Slip Casting Membrane Preparation The method consisted of suspending zirconia and polyvinyl alcohol in distilled water and pouring the produced slip inside the porous support Figure 2 The method results in the controlled diffusion process which amounts to a simple loss of water from the suspension in the mass of the support this causes the accumulation of zirconia particles on its surface The support sintered with thermal sequences ensures that the material can withstand high pressures and chemical attacks However zircon oxide ZrO2 accumulated in the inner part of the tubular support provides the formation of selective permeable membrane The method of zirconiabased ceramic membrane preparation can be summarized in the following steps Take 70 of the distilled water and add in 4 by weight of ZrO2 powder to mix the mixture until a good homogeneous mixture was obtained Place the mixture in an ultrasonic bath for 10 min to dispel the granules and dissolve the sediments Then add 26 polyvinyl alcohol PVA and mix for 12 h to obtain the suspension solution The solution is poured into the support for 10 min and dried for 5 min Symmetry 2020 12 933 5 of 15 Symmetry 2019 11 x FOR PEER REVIEW 5 of 16 Figure 2 The method for preparing the slip casting membrane 24 Experimental Setup of Filtration The prepared zirconiabased ceramic membrane was used for the treatment of drinking water obtained from Oued El Athmania water treatment plant Mila Algeria The filtration experiments were carried out using a tangential filtration system Figure 3 The total volume of the reservoir was 5 L and 3 L of drinking water was used for each experiment The effective membrane area was 45 cm2 and crossflow velocity was 418 ms The concentrate was recycled back into the feed tank and the filtered water permeate was collected in an Erlenmeyer flask for analysis The volume of filtrate was monitored as a function of time to determine the permeate flux Jp Figure 3 Experimental setup of the tangential filtration system reservoir 1 tangential membrane 2 module 3 pressure gauge 4 flowmeter 5 valve 6 pump 7 permeate 8 Figure 2 The method for preparing the slip casting membrane 24 Experimental Setup of Filtration The prepared zirconiabased ceramic membrane was used for the treatment of drinking water obtained from Oued El Athmania water treatment plant Mila Algeria The filtration experiments were carried out using a tangential filtration system Figure 3 The total volume of the reservoir was 5 L and 3 L of drinking water was used for each experiment The effective membrane area was 45 cm2 and crossflow velocity was 418 ms The concentrate was recycled back into the feed tank and the filtered water permeate was collected in an Erlenmeyer flask for analysis The volume of filtrate was monitored as a function of time to determine the permeate flux Jp Symmetry 2019 11 x FOR PEER REVIEW 5 of 16 Figure 2 The method for preparing the slip casting membrane 24 Experimental Setup of Filtration The prepared zirconiabased ceramic membrane was used for the treatment of drinking water obtained from Oued El Athmania water treatment plant Mila Algeria The filtration experiments were carried out using a tangential filtration system Figure 3 The total volume of the reservoir was 5 L and 3 L of drinking water was used for each experiment The effective membrane area was 45 cm2 and crossflow velocity was 418 ms The concentrate was recycled back into the feed tank and the filtered water permeate was collected in an Erlenmeyer flask for analysis The volume of filtrate was monitored as a function of time to determine the permeate flux Jp Figure 3 Experimental setup of the tangential filtration system reservoir 1 tangential membrane 2 module 3 pressure gauge 4 flowmeter 5 valve 6 pump 7 permeate 8 Figure 3 Experimental setup of the tangential filtration system reservoir 1 tangential membrane 2 module 3 pressure gauge 4 flowmeter 5 valve 6 pump 7 permeate 8 Symmetry 2020 12 933 6 of 15 25 Determination Method of Total Coliform Bacteria Coliform bacteria filtration experiments were also carried out by prepared ceramic membrane Coliform bacteria in water thermotolerant coliforms and E coli were investigated and counted using the most probable number MPN technique in liquid medium BCP Bromocresol Purple Lactose Broth Tubes were used for presumptive identification and enrichment of total coliforms including thermotolerant coliforms Water samples were collected in sterile glass bottles 1 L in order to detect and count the final concentration of bacteria after filtration The final reading was carried out according to the requirements of the MPN table taking into account that E Coli is a producer of gas and indole at 44 C 3 Results 31 Characterization of the Support and ZirconiaBased Ceramic Membrane The characterizations of the support and zirconiabased ceramic membrane are given in Tables 2 and 3 Table 2 The characteristics of the tubular kaolin support Properties Support Material Outside diameter 9 mm Inside diameter 46 mm Thickness 22 mm Length 190 mm Operating pH range 114 Washing pH range 114 Table 3 The characteristics of the tubular zirconiabased ceramic membrane Properties Ceramic Membrane Total area 448 103 m2 Average pore diameter 02 µm Operating pH range 114 Washing pH range 114 311 Scanning Electron Microscopy SEM Scanning Electron Microscopy allows for the observation of the morphology and cavities of the membranesupport inner and outer surfaces It should be remembered that the slip casting membrane was deposited inside the tubular support Figure 4AB show the outer surface of the support material It could be seen from the figures that there were large and irregular pores on the support layer Figure 4CD show the inner surface of the ceramic membrane The layered structure of zirconia and the asymmetric distribution of the pores can be seen from the figures Moreover crosssection images of the tubular membrane are seen in Figure 4EF The outer surface of the support had wider cavities compared to the inner surface These cavities can be considered to be an advantage for deposition or adhesion of the solution inside the module Symmetry 2020 12 933 7 of 15 Symmetry 2019 11 x FOR PEER REVIEW 7 of 16 Figure 4 SEM images of the support and ceramic membrane AB the outer surface of the support material CD the inner surface of the ceramic membrane EF crosssection of the tubular membrane 312 XRay Fluorescence XRF The XRay fluorescence analyses were carried out by a Panalytical Epsilon 3 spectrophotometer for the evaluation of the most present elements in the membrane support This energy dispersive X Ray spectrophotometer was connected to a computer using the Omnian analysis software The sample was placed under helium flow during the analysis Fluorescence Xray spectra were recorded under different excitation conditions The use of a particular filter with a potential difference and a particular current allows for the better exploration of a particular region of the spectrum For the support material the first spectrum was realized with a potential difference dp of 500 keV and a current of 1000 μA Figure 5A It allowed us to explore the region of energies up to about 4 keV For the zirconiabased ceramic membrane the second spectrum was realized with a silver filter with a thickness of 100 μ a dp of 3000 keV and a current of 300 μA Figure 5B It allows the peaks of high energy to be observed However in this case the peaks are strongly attenuated From the spectrograms of Figure 5AB excitation energy spectra in the range of 1486 to 1597 keV and 1739 to 1836 keV corresponding to atoms Al and Si respectively come from aluminum silicate Al2SiO5 the clay material Moreover in the spectrogram of Figure 5B the excitation energy spectrum of 15744 keV Figure 4 SEM images of the support and ceramic membrane AB the outer surface of the support material CD the inner surface of the ceramic membrane EF crosssection of the tubular membrane 312 Xray Fluorescence XRF The Xray fluorescence analyses were carried out by a Panalytical Epsilon 3 spectrophotometer for the evaluation of the most present elements in the membrane support This energy dispersive Xray spectrophotometer was connected to a computer using the Omnian analysis software The sample was placed under helium flow during the analysis Fluorescence Xray spectra were recorded under different excitation conditions The use of a particular filter with a potential difference and a particular current allows for the better exploration of a particular region of the spectrum For the support material the first spectrum was realized with a potential difference dp of 500 keV and a current of 1000 µA Figure 5A It allowed us to explore the region of energies up to about 4 keV For the zirconiabased ceramic membrane the second spectrum was realized with a silver filter with a thickness of 100 µ a dp of 3000 keV and a current of 300 µA Figure 5B It allows the peaks of high energy to be observed However in this case the peaks are strongly attenuated From the spectrograms of Figure 5AB excitation energy spectra in the range of 1486 to 1597 keV and 1739 to 1836 keV corresponding to atoms Al and Si respectively come from aluminum silicate Al2SiO5 the clay material Moreover in the spectrogram of Figure 5B Symmetry 2020 12 933 8 of 15 the excitation energy spectrum of 15744 keV corresponding to the zirconia atom Zr constituent of the zirconia oxide ZrO2 membrane was noted Zirconia detected in the ceramic membrane showed that zirconia had entered the structure of the support material Symmetry 2019 11 x FOR PEER REVIEW 8 of 16 excitation energy spectra in the range of 1486 to 1597 keV and 1739 to 1836 keV corresponding to atoms Al and Si respectively come from aluminum silicate Al2SiO5 the clay material Moreover in the spectrogram of Figure 5B the excitation energy spectrum of 15744 keV corresponding to the zirconia atom Zr constituent of the zirconia oxide ZrO2 membrane was noted Zirconia detected in the ceramic membrane showed that zirconia had entered the structure of the support material It was also found from the spectrograms of Figure 5CD that the clay used in the preparation of the support contained other constituents such as Mn and Fe We also noticed excitation energy spectra in the range of 35 to 4 keV which confirmed the presence of the calcium Ca It composed the calcium oxide CaO by addition of calcite CaCO3 transformed into CaO during the heat treatment of the support paste Figure 5 XRay Fluorescence XRF spectrum of the support A C D and ceramic membraneB 313 XRay Diffraction XRD The support was characterized by a Panalytical Empyrian brand diffractometer operating under the following conditions 40 mA 45 kV with monochromatic radiation Kα 154 A of copper equipped with a goniometer and an Xray detector Figure 6 represents XRD reflections of the support at a temperature of 1100 C for 1 h The main phase identified in the membrane support was the anorthite CaO Al2O3 2SiO2 which was a predominant phase This phase was very important because of its promising physical and mechanical properties 529 Figure 5 Xray Fluorescence XRF spectrum of the support ACD and ceramic membrane B It was also found from the spectrograms of Figure 5CD that the clay used in the preparation of the support contained other constituents such as Mn and Fe We also noticed excitation energy spectra in the range of 35 to 4 keV which confirmed the presence of the calcium Ca It composed the calcium oxide CaO by addition of calcite CaCO3 transformed into CaO during the heat treatment of the support paste 313 Xray Diffraction XRD The support was characterized by a Panalytical Empyrian brand diffractometer operating under the following conditions 40 mA 45 kV with monochromatic radiation Kα 154 A of copper equipped with a goniometer and an Xray detector Figure 6 represents XRD reflections of the support at a temperature of 1100 C for 1 h The main phase identified in the membrane support was the anorthite CaO Al2O3 2SiO2 which was a predominant phase This phase was very important because of its promising physical and mechanical properties 529 Symmetry 2020 12 933 9 of 15 Symmetry 2019 11 x FOR PEER REVIEW 9 of 16 Figure 6 Diffractogram of the clay support 314 FourierTransform Infrared Spectroscopy FTIR Infrared spectra were recorded on a spectrophotometer equipped with an ATR accessory Jasco FTIR4000 Infrared spectroscopy is a tool for mineralogists to characterize the crystallinity of materials by observing the relative intensities of the hydroxyl OH vibration bands and that of the SiO SiOSi AlOH and AlO in their structures 3031 The IR spectrogram of the clay support represented by Figure 7 was divided into two main zones The first peaks corresponded to high frequency bands wave numbers between 3700 and 2800 cm1 and the second peaks corresponded to the lower frequencies located in the 1500500 cm1 area The high frequency bands zone II concerned the vibration of OH hydroxyls while the low frequency bands zone I related to the SiO SiOSi AlOHAl AlOH and AlO bond networks 32 Figure 6 Diffractogram of the clay support 314 FourierTransform Infrared Spectroscopy FTIR Infrared spectra were recorded on a spectrophotometer equipped with an ATR accessory Jasco FTIR4000 Infrared spectroscopy is a tool for mineralogists to characterize the crystallinity of materials by observing the relative intensities of the hydroxyl OH vibration bands and that of the SiO SiOSi AlOH and AlO in their structures 3031 The IR spectrogram of the clay support represented by Figure 7 was divided into two main zones The first peaks corresponded to high frequency bands wave numbers between 3700 and 2800 cm1 and the second peaks corresponded to the lower frequencies located in the 1500500 cm1 area The high frequency bands zone II concerned the vibration of OH hydroxyls while the low frequency bands zone I related to the SiO SiOSi AlOHAl AlOH and AlO bond networks 32 Symmetry 2019 11 x FOR PEER REVIEW 10 of 16 Figure 7 IR spectrogram of the support The wave numbers υ of peaks and the functional groups corresponding to kaolin are summarized in Table 4 According to Table 2 in correlation with the literature it was found that the clay used as support contained the different chemical elements with different percentages such as Si Al Fe and bonds with hydroxyls which has been confirmed by several authors 3335 Table 4 Attribution of vibration bands of IR spectra of clay materials Wave Number υ in cm1 of the Clay Support Wave Number υ in cm1 Observed in Literature Kaolin Band Assignment 3670 3695 3670 ν OH interlayer ν OH grain surface 1070 1096 10101033 νSiO νSiOSi 897 875 937 912915 AlOHFe3 δAlOHAl intern with Feuillet δAlOHAl external with layer 780 760 800778 757700 SiO of Quartz AlOH 540 540 AlO 315 Raman Spectroscopy The Raman scattering spectra were collected by a Thermo Fisher DXR spectrometer equipped with an optical microscope a threegrating monochromator triple additive mode and a CCD camera Figure 7 IR spectrogram of the support Symmetry 2020 12 933 10 of 15 The wave numbers υ of peaks and the functional groups corresponding to kaolin are summarized in Table 4 According to Table 2 in correlation with the literature it was found that the clay used as support contained the different chemical elements with different percentages such as Si Al Fe and bonds with hydroxyls which has been confirmed by several authors 3335 Table 4 Attribution of vibration bands of IR spectra of clay materials Wave Number υ in cm1 of the Clay Support Wave Number υ in cm1 Observed in Literature Kaolin Band Assignment 3670 3695 ν OH interlayer 3670 ν OH grain surface 1070 1096 νSiO 10101033 νSiOSi 897 875 AlOHFe3 937 δAlOHAl intern with Feuillet 912915 δAlOHAl external with layer 780 800778 SiO of Quartz 760 757700 AlOH 540 540 AlO 315 Raman Spectroscopy The Raman scattering spectra were collected by a Thermo Fisher DXR spectrometer equipped with an optical microscope a threegrating monochromator triple additive mode and a CCD camera detector Charge Coupled Device The exciting radiation of a wavelength of 780 nm was delivered by the beam of a NIR diode laser The beam was focused with a long frontal lens 100 magnification numerical aperture of 09 over 50 µm of the sample surface The power irradiating the sample was about 10 mW The scattered retro Raman spectrum was collected in confocal mode to avoid optical artifacts particularly the signal from the glass slide above the sample cell The spectral resolution was 19 cm1 with a precision on the measurement of the best wave number only 1 cm1 Figure 8 represents the Raman spectrum of the clay support where several bands were observed We noticed the appearance of new spectra at 1694 2080 and 3372 cm1 which express the vibrations of ν CO SiH and OH respectively 36 Symmetry 2019 11 x FOR PEER REVIEW 11 of 16 detector Charge Coupled Device The exciting radiation of a wavelength of 780 nm was delivered by the beam of a NIR diode laser The beam was focused with a long frontal lens 100 magnification numerical aperture of 09 over 50 µm of the sample surface The power irradiating the sample was about 10 mW The scattered retro Raman spectrum was collected in confocal mode to avoid optical artifacts particularly the signal from the glass slide above the sample cell The spectral resolution was 19 cm1 with a precision on the measurement of the best wave number only 1 cm1 Figure 8 represents the Raman spectrum of the clay support where several bands were observed We noticed the appearance of new spectra at 1694 2080 and 3372 cm1 which express the vibrations of ν C O SiH and OH respectively 36 Figure 8 Raman spectrogram of the clay support 32 Filtration Experiments 321 Permeate Flux Variation Versus TMP and Time Figure 9A shows that the permeate flux Jp of distilled water increases with the increase in the transmembrane pressure TMP according to the Darcy law 37 The variations of the permeate flux Jp versus time using distilled and raw drinking water are presented in Figure 9B According to the obtained results it can be seen that the permeate flux for the distilled and the raw water were not of the same order This behavior can be explained by the retention of certain matters by the ceramic membrane causing a blockage of the pores which leads to the reduction of the amount of water passing through the membrane permeate The straight line for distilled water explains that the flow of water was constant over the filtration time On the other hand the permeate flux of raw drinking water decreased during the first 20 min and then became constant It could be explained by there being a certain amount of suspended matter which had deposited on the surface of the membrane Figure 8 Raman spectrogram of the clay support Symmetry 2020 12 933 11 of 15 32 Filtration Experiments 321 Permeate Flux Variation versus TMP and Time Figure 9A shows that the permeate flux Jp of distilled water increases with the increase in the transmembrane pressure TMP according to the Darcy law 37 The variations of the permeate flux Jp versus time using distilled and raw drinking water are presented in Figure 9B According to the obtained results it can be seen that the permeate flux for the distilled and the raw water were not of the same order This behavior can be explained by the retention of certain matters by the ceramic membrane causing a blockage of the pores which leads to the reduction of the amount of water passing through the membrane permeate The straight line for distilled water explains that the flow of water was constant over the filtration time On the other hand the permeate flux of raw drinking water decreased during the first 20 min and then became constant It could be explained by there being a certain amount of suspended matter which had deposited on the surface of the membrane Symmetry 2019 11 x FOR PEER REVIEW 12 of 16 Figure 9 A Variation of permeate flux Jp of distilled water versus transmembrane pressure TMP B Variation of permeate flux of distilled and raw drinking water versus filtration time at TPM 08 bar 322 Turbidity Variation Versus Time Turbidity was determined using a 2100Q portable turbidimeter proposed by Hach with a tungsten filament lamp equipped with a twodetector ratio optical system for accurate results during routine analyses It brings greater measurement sensitivity over a wider range of 0 to 1000 NTU The suspended solid in water causes turbidity The membrane filtration experiments were carried out for raw drinking water obtained from Oued El Athmania water treatment plant The turbidity of raw drinking water increased in the concentrate versus filtration time because the water was completely recycled into the feed tank Figure 10 Figure 10 Turbidity variation of the permeate and concentrate versus filtration time at TMP 08 bar The characterizations of raw drinking water permeate and concentrate quality are presented in Table 5 Figure 9 A Variation of permeate flux Jp of distilled water versus transmembrane pressure TMP B Variation of permeate flux of distilled and raw drinking water versus filtration time at TPM 08 bar 322 Turbidity Variation Versus Time Turbidity was determined using a 2100Q portable turbidimeter proposed by Hach with a tungsten filament lamp equipped with a twodetector ratio optical system for accurate results during routine analyses It brings greater measurement sensitivity over a wider range of 0 to 1000 NTU The suspended solid in water causes turbidity The membrane filtration experiments were carried out for raw drinking water obtained from Oued El Athmania water treatment plant The turbidity of raw drinking water increased in the concentrate versus filtration time because the water was completely recycled into the feed tank Figure 10 Symmetry 2019 11 x FOR PEER REVIEW 12 of 16 Figure 9 A Variation of permeate flux Jp of distilled water versus transmembrane pressure TMP B Variation of permeate flux of distilled and raw drinking water versus filtration time at TPM 08 bar 322 Turbidity Variation Versus Time Turbidity was determined using a 2100Q portable turbidimeter proposed by Hach with a tungsten filament lamp equipped with a twodetector ratio optical system for accurate results during routine analyses It brings greater measurement sensitivity over a wider range of 0 to 1000 NTU The suspended solid in water causes turbidity The membrane filtration experiments were carried out for raw drinking water obtained from Oued El Athmania water treatment plant The turbidity of raw drinking water increased in the concentrate versus filtration time because the water was completely recycled into the feed tank Figure 10 Figure 10 Turbidity variation of the permeate and concentrate versus filtration time at TMP 08 bar The characterizations of raw drinking water permeate and concentrate quality are presented in Table 5 Figure 10 Turbidity variation of the permeate and concentrate versus filtration time at TMP 08 bar Symmetry 2020 12 933 12 of 15 The characterizations of raw drinking water permeate and concentrate quality are presented in Table 5 Table 5 The properties of raw drinking water permeate and concentrate PhysicoChemical Parameters Units Raw Water Permeate Concentrate pH 835 817 839 Conductivity µScm 1120 1100 1133 Dissolved Salt Rate DSR mgL 617 610 631 Turbidity NTU 810 069 2110 Total hardness mgL 400 380 410 Phosphate PO43 mgL 007 000 016 Ammonium NH4 mgL 003 002 006 Nitrite NO2 mgL 00 00 00 Nitrate NO3 mgL 700 618 740 Ferrous iron Fe2 mgL 017 003 033 Manganese Mn2 mgL 01 00 07 Aluminum Al3 mgL 00 00 00 Zinc Zn2 mgL 043 030 060 Chloride Cl mgL 17727 17372 18081 Calcium Ca2 mgL 8417 8016 9218 323 Total Coliform Bacteria Variation versus Time Biological tests of total coliform bacteria were also performed in this work to test the retention capacity of the ceramic membrane E coli are considered as indicators of the microbial quality of drinking water 38 In the filtered water permeate the number of coliforms was equal to zero during 60 min filtration which depicted that all of the total coliforms were rejected by the zirconiabased ceramic membrane Figure 11 On the other hand in the concentrated water an increase in the number of total coliforms from 15 to 35 in 100 mL was obtained after 60 min of filtration Symmetry 2019 11 x FOR PEER REVIEW 13 of 16 Table 5 The properties of raw drinking water permeate and concentrate Physicochemical Parameters Units Raw Water Permeate Concentrate pH 835 817 839 Conductivity µScm 1120 1100 1133 Dissolved Salt Rate DSR mgL 617 610 631 Turbidity NTU 810 069 2110 Total hardness mgL 400 380 410 Phosphate PO43 mgL 007 000 016 Ammonium NH4 mgL 003 002 006 Nitrite NO2 mgL 00 00 00 Nitrate NO3 mgL 700 618 740 Ferrous iron Fe2 mgL 017 003 033 Manganese Mn2 mgL 01 00 07 Aluminum Al3 mgL 00 00 00 Zinc Zn2 mgL 043 030 060 Chloride Cl mgL 17727 17372 18081 Calcium Ca2 mgL 8417 8016 9218 323 Total Coliform Bacteria Variation Versus Time Biological tests of total coliform bacteria were also performed in this work to test the retention capacity of the ceramic membrane E coli are considered as indicators of the microbial quality of drinking water 38 In the filtered water permeate the number of coliforms was equal to zero during 60 min filtration which depicted that all of the total coliforms were rejected by the zirconia based ceramic membrane Figure 11 On the other hand in the concentrated water an increase in the number of total coliforms from 15 to 35 in 100 mL was obtained after 60 min of filtration Figure 11 Evolution of the number of total coliforms in the permeate and concentrate and versus time 4 Conclusions In this work a zirconiabased ceramic membrane with a tubular configuration was prepared by the casting method The anorthite support which had favorable physical and mechanical properties Figure 11 Evolution of the number of total coliforms in the permeate and concentrate and versus time Symmetry 2020 12 933 13 of 15 4 Conclusions In this work a zirconiabased ceramic membrane with a tubular configuration was prepared by the casting method The anorthite support which had favorable physical and mechanical properties was prepared by the extrusion method The inner layer containing smaller pores compared to the support reduced the size of the pores and eliminated defects of the support The membrane filtration results showed that there was an improvement in the physicochemical and bacteriological quality of raw drinking water The prepared membrane retained all of the total coliforms Using a ceramic membrane can help to obtain a good clarification and can reduce the addition of chemical agents such as aluminum and chlorine used for coagulation and disinfection These agents form an additional pollution such as the presence of aluminum in the sludge from the settling basin and an acceptable taste of water after the addition of a smaller amount of chlorine Author Contributions This work was carried out by the contribution of all the authors cited in this paper the author MB was interested to the experimental preparation of a Zirconiabased ceramic membrane The other authors focused on the characterization of the membrane support Xray fluorescence XRF was devoted to BK Xray diffraction and FTIR were carried out by FB Raman Spectroscopy by YO the SEM and the experimental part of filtration as well as the discussion of all the results were carried out by ND MC and MB All authors have read and agreed to the published version of the manuscript Funding This research received no external funding Acknowledgments We would like to thank Farhat Bouzerara Lecturer at the University of Jijel for his help to realize the ceramic membrane Conflicts of Interest The authors declare no conflict of interest References 1 Lee SH Chung KC Shin MC Dong JI Lee HS Auh KH Preparation of ceramic membrane and application to the crossflow microfiltration of soluble waste oil Mater Lett 2002 52 266271 CrossRef 2 Oh HK Takizawa S Ohgaki S Katayama H Oguma K Yu MJ Removal of organics and viruses using hybrid ceramic MF system without draining PAC Desalination 2007 202 191198 CrossRef 3 Emani S Uppaluri R Purkait MK Preparation and characterization of low cost ceramic membranes for mosambi juice clarification Desalination 2013 317 3240 CrossRef 4 Bouazizi A Saja S Achiou B Ouammou M Calvo JI Aaddane A Younssi SA Elaboration and characterization of a new flat ceramic MF membrane made from natural Moroccan bentonite Application to treatment of industrial wastewater Appl Clay Sci 2016 132133 3340 CrossRef 5 Ghouil B Harabi A Bouzerara F Boudaira B Guechi A Demir MM Figoli A Development and characterization of tubular composite ceramic membranes using natural aluminosilicates for microfiltration applications Mater Charact 2015 103 1827 CrossRef 6 Jana S Purkait MK Mohanty K Preparation and Characterizations of Ceramic Microfiltration Membrane Effect of Inorganic Precursors on Membrane Morphology Sep Sci Technol 2010 46 3345 CrossRef 7 Verweij H Inorganic membranes Curr Opin Chem Eng 2012 1 156162 CrossRef 8 Ismail AF Chandra Khulbe K Matsuura T Gas Separation Membranes Springer International Publishing BerlinHeidelberg Germany 2015 ISBN 9783319010946 9 Weir M Fabrication characterization and preliminary testing of allinorganic ultrafiltration membranes composed entirely of a naturally occurring sepiolite clay mineral J Membr Sci 2001 182 4150 CrossRef 10 Murray HH Traditional and new applications for kaolin smectite and palygorskite A general overview Appl Clay Sci 2000 17 207221 CrossRef 11 Bouzerara F Harabi A Ghouil B Medjemem N Boudaira B Condom S Elaboration and Properties of Zirconia Microfiltration Membranes Procedia Eng 2012 33 278284 CrossRef 12 Yousefi V MohebbiKalhori D Samimi A Ceramicbased microbial fuel cells MFCs A review Int J Hydrogen Energy 2017 42 16721690 CrossRef 13 Xing WH Ceramic Membranes In MembraneBased Separations in Metallurgy Elsevier Amsterdam The Netherlands 2017 pp 357370 ISBN 9780128034279 Symmetry 2020 12 933 14 of 15 14 Zhang S Wang R Zhang S Li G Zhang Y Treatment of wastewater containing oil using phosphorylated silica nanotubes PSNTspolyvinylidene fluoride PVDF composite membrane Desalination 2014 332 109116 CrossRef 15 Kayvani Fard A McKay G Buekenhoudt A Al Sulaiti H Motmans F Khraisheh M Atieh M Inorganic Membranes Preparation and Application for Water Treatment and Desalination Materials Basel 2018 11 74 CrossRef PubMed 16 Das B Chakrabarty B Barkakati P Preparation and characterization of novel ceramic membranes for microfiltration applications Ceram Int 2016 42 1432614333 CrossRef 17 Goh PS Ismail AF A review on inorganic membranes for desalination and wastewater treatment Desalination 2018 434 6080 CrossRef 18 Suriyakumar S Raja M Angulakshmi N Nahm KS Stephan AM A flexible zirconium oxide basedceramic membrane as a separator for lithiumion batteries RSC Adv 2016 6 9202092027 CrossRef 19 Wang P A pilot study of the treatment of waste rolling emulsion using zirconia microfiltration membranes J Membr Sci 2000 173 159166 CrossRef 20 Zhou J Chang Q Wang Y Wang J Meng G Separation of stable oilwater emulsion by the hydrophilic nanosized ZrO2 modified Al2O3 microfiltration membrane Sep Purif Technol 2010 75 243248 CrossRef 21 Zhong J Sun X Wang C Treatment of oily wastewater produced from refinery processes using flocculation and ceramic membrane filtration Sep Purif Technol 2003 32 9398 CrossRef 22 Kroll S Treccani L Rezwan K Grathwohl G Development and characterisation of functionalised ceramic microtubes for bacteria filtration J Membr Sci 2010 365 447455 CrossRef 23 Krajewski SR Kujawski W Dijoux F Picard C Larbot A Grafting of ZrO2 powder and ZrO2 membrane by fluoroalkylsilanes Colloids Surf A Physicochem Eng Asp 2004 243 4347 CrossRef 24 Larbot A Gazagnes L Krajewski S Bukowska M Kujawski W Water desalination using ceramic membrane distillation Desalination 2004 168 367372 CrossRef 25 Kumar RV Ghoshal AK Pugazhenthi G Fabrication of zirconia composite membrane by insitu hydrothermal technique and its application in separation of methyl orange Ecotoxicol Environ Saf 2015 121 7379 CrossRef 26 Erdem I Çiftçioglu M Harsa S Separation of whey components by using ceramic composite membranes Desalination 2006 189 8791 CrossRef 27 Dey S Bhattacharya P Bandyopadhyay S Roy SN Majumdar S Sahoo GC Single step preparation of zirconia ultrafiltration membrane over clayalumina based multichannel ceramic support for wastewater treatment J Membr Sci Res 2018 4 2833 28 Abdullayev A Bekheet MF Hanaor DAH Gurlo A Materials and applications for lowcost ceramic membranes Membranes Basel 2019 9 105 CrossRef 29 Zenikheri F Harabi A Boudaira B Bouzerara F Guechi A Barama SE Foughali L Karboua N Elaboration of porous gehlenite and anorthite based ceramics using low price raw materials Cerâmica 2016 62 242248 CrossRef 30 Kolli M Hamidouche M Fantozzi G Chevalier J Elaboration and characterization of a refractory based on Algerian kaolin Ceram Int 2007 33 14351443 CrossRef 31 Ouali A Sahnoune F Belhouchet H Heraiz M Effect of CaO addition on the sintering behaviour of anorthite formed from kaolin and CaO Acta Phys Pol A 2017 131 159161 CrossRef 32 MukasaTebandeke IZ Ssebuwufu PJM Nyanzi SA Schumann A Nyakairu GWA Ntale M Lugolobi F The Elemental Mineralogical IR DTA and XRD Analyses Characterized Clays and Clay Minerals of Central and Eastern Uganda Adv Mater Phys Chem 2015 5 6786 CrossRef 33 MacíasQuiroga IF GiraldoGómez GI SanabriaGonzález NR Characterization of Colombian Clay and Its Potential Use as Adsorbent Sci World J 2018 2018 111 CrossRef 34 Hosseini SA Niaei A Salari D Production of γAl2O3 from Kaolin Open J Phys Chem 2011 1 2327 CrossRef 35 Johnston CT Elzea Kogel J Bish DL Kogure T Murray HH Lowtemperature Ftir Study of KaolinGroup Minerals Clays Clay Miner 2008 56 470485 CrossRef 36 Saikia BJ Parthasarathy G Borah RR Borthakur R Raman and FTIR Spectroscopic Evaluation of Clay Minerals and Estimation of Metal Contaminations in Natural Deposition of Surface Sediments from Brahmaputra River Int J Geosci 2016 7 873883 CrossRef Symmetry 2020 12 933 15 of 15 37 Chikhi M Meniai AH Balaska F BencheikhLehocine M Modeling of the Ultrafiltration of a Dextran T500 Solution in a Tubular Membrane Module Chem Eng Technol 2008 31 501506 CrossRef 38 Bottino A Capannelli C Del Borghi A Colombino M Conio O Water treatment for drinking purpose Ceramic microfiltration application Desalination 2001 141 7579 CrossRef 2020 by the authors Licensee MDPI Basel Switzerland This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution CC BY license httpcreativecommonsorglicensesby40