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This study explored using ultrafiltration (UF) membranes to treat pulp and paper mill wastewater, implementing a novel Taguchi experimental design to optimize operating conditions for pollutant removal and minimal membrane fouling. Researchers examined four factors: pH, temperature, transmembrane pressure, and volume reduction factor (VRF), each at three levels. Optimal conditions (pH 10, 25°C, 6 bar, VRF 3) led to a 35% reduction in flux due to fouling and high pollutant rejections: total hardness (83%), sulfate (97%), spectral absorption coefficient (SAC254) (95%), and chemical oxygen demand (COD) (89%). Conductivity had a lower rejection rate of 50%. Advanced imaging techniques like atomic force microscopy (AFM) and scanning electron microscopy (SEM) revealed reduced membrane fouling under these conditions. The Taguchi method effectively identified optimal conditions, significantly improving wastewater treatment efficiency and promoting environmental sustainability in the pulp and paper industry. Practitioner Points: This study optimized UF membrane conditions for pulp and paper mill wastewater, reducing fouling and enhancing pollutant removal, offering practical strategies for industrial treatment.AFM and SEM provided key insights into membrane fouling and mitigation, promoting real‐time diagnosis and optimization for enhanced treatment efficiency.Prioritizing anaerobic fixed‐bed systems in wastewater treatment is beneficial for achieving high COD removal efficiency. Optimizing hydraulic retention time (HRT) in these systems can further improve their overall effectiveness and sustainability. [ABSTRACT FROM AUTHOR]

Dye hurts the threat of human health problems and environmental pollution. Microcrystalline cellulose (MCC) based membrane is a good material to be used as an dye separation membrane for having the high hydrophilicity of the membrane. It has been successfully isolated from kapok (ceiba pentandra) with characteristic X-ray diffraction patterns and FTIR absorption peaks, which corresponded to the typical peaks of cellulose. The ultrafiltration membrane was made up of a cellulose acetate matrix created using the phase inversion method. Characterization results indicated that the inclusion of MCC derived from kapok led to a reduction in the contact angle from 65 to 52o, and an increase in membrane porosity from 82 to 85%. In the separation of dye, the composite membrane incorporating MCC filler demonstrated superior performance compared to the membrane lacking MCC, manifesting in an elevated water flux from 43 to 84 L/m².h and methylene blue (MB) rejection from 64 to 99%. The use of MCC as a filler in cellulose acetate membranes can enhance the characteristics and performance of the membrane in MB separation.

This study seeks to increase the antifouling properties of fluorinated polyvinylidene (PVDF) membranes through the synergistic application of plasma treatment and polymer deposition, employing polymerizations of polyvinylpyrrolidone (PVP) and polyethyleneimine (PEI). The results show remarkable success in modifications, presenting exceptional performance. Two distinct surface modification methods, plasma treatment and polymer deposition, were used to improve the antifouling properties and filtration performance of PVDF membranes. The plasma used was a discharge dielectric barrier using ambient air as gas, and hydrophilic polymers, PVP, and PEI. The results outlined changes in membrane roughness with a significant roughness reduction of up to 43% evident based on topographic and morphological analyses. Hydraulic permeability analysis revealed a substantial 35‐fold increase, indicating a notable improvement in performance. All treated membranes exhibited higher water affinity and superior performance during 12‐h ultrafiltration compared to their untreated counterparts. After chemical cleaning, water flux recovery exceeded 85% for all treated membranes, indicating the inherent antifouling properties of the surface. [ABSTRACT FROM AUTHOR]

Our research focuses on developing environmentally friendly biodegradable ultrafiltration (UF) membranes for small-scale water purification in areas lacking infrastructure or during emergencies. To address biofouling challenges without resorting to harmful chemicals, we incorporate bio-based extracts, such as methyl gallate from A. occidentale leaves, a Malaysian ulam herb, known for its quorum sensing inhibition (QSI) properties. The methyl gallate enriched extract was purified by solvent partitioning and integrated into cellulose-based UF membranes (0 to 7.5% w w–1) through phase inversion technique. The resulting membranes exhibited enhanced anti-organic fouling and anti-biofouling properties, with flux recovery ratio (FRR) of 87.84 ± 2.00% against bovine serum albumin and FRRs of 76.67 ± 1.89% and 69.57 ± 1.77% against E. coli and S. aureus, respectively. The CA/MG-5 membrane showed a 224% improvement in pure water flux (PWF) compared to the neat CA membrane. Our innovative approach significantly improves PWF, presenting an environmentally friendly method for biofouling prevention in UF membrane applications. [ABSTRACT FROM AUTHOR]

BACKGROUND: In this work, a polyphenylsulfone/polyethersulfone (PPSU/PES) composite membrane was successfully prepared using the phase‐inversion method in the presence of polyethylene glycol (PEG) as a hydrophilic additive. The effect of concentration of PEG (0, 2, 4 and 6 wt%) was investigated by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and contact angle analysis. RESULTS: The obtained results confirmed that the morphology and hydrophilicity of the porous membrane varied with the addition of PES as reinforcing agent and the PEG concentration as porogen. SEM results confirmed that the membranes obtained have a high permeability with a finger‐shaped structure and that the size and density of the pores increase with an increase in the incorporated PEG. The contact angle was decreased and the porosity of the PPPn blend membranes was increased from 16.06 for the neat PPSU membrane to 385.3 L h−1 m−2 bar−1 for the PPP6 membrane. A strong interaction between the components (PPSU, PES and PEG) was revealed by FTIR spectroscopy and TGA. CONCLUSION: The filtration results showed that PPP2 is the better formulation of the dope suspension in the range of ultrafiltration membranes in terms of flux (179.3 L h−1 m−2 bar−1) and bovine serum albumin retention (94%). The application of polyelectrolyte‐enhanced ultrafiltration using polyethylenimine (PEI) for the removal of cobalt ions afforded high removal rates (92.5%). The optimal performances were obtained at pH ≥ 4, transmembrane pressure of 4 bar and 1200 ppm of PEI. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Emerging antibiotic contaminants in water is a global problem because bacterial strains resistant to these antibiotics arise, risking human health. This study describes the use of poly[(4-vinylbenzyl) trimethylammonium chloride] and N-alkylated chitosan, two cationic polymers with different natures and structures to remove nalidixic acid. Both contain ammonium salt as a functional group. One of them is a synthetic polymer, and the other is a modified artificial polymer. The removal of the antibiotic was investigated under various experimental conditions (pH, ionic strength, and antibiotic concentration) using the technique of liquid-phase polymer-based retention (LPR). In addition, a stochastic algorithm provided by Fukui's functions is used. It was shown that alkylated N-chitosan presents 65.0% removal at pH 7, while poly[(4-vinylbenzyl)trimethylammonium chloride] removes 75.0% at pH 9. The interaction mechanisms that predominate the removal processes are electrostatic interactions, π–π interactions, and hydrogen bonding. The polymers reached maximum retention capacities of 1605 mg g−1 for poly[(4-vinylbenzyl) trimethylammonium chloride] and 561 mg g−1 of antibiotic per gram for alkylated poly(N-chitosan). In conclusion, the presence of aromatic groups improves the capacity and polymer–antibiotic interactions. [ABSTRACT FROM AUTHOR]

The application of separation technology using ultrafiltration/nanofiltration membranes for protein purification and concentration has grown rapidly in the last decade. Innovations to synthesize membranes with properties and performance that suit the characteristics of the feed solution have been and will keep developing. This study aims to examine the strategies to improve the performance of the Polyvinylidene Fluoride (PVDF) membrane for lactalbumin protein isolation. The PVDF polymer membrane was modified by adding Poloxamer 188 (Po1) copolymer and a combination of two types of nanocarbons, i.e., single-walled carbon nanotubes (S-CnT) and multi-walled carbon nanotubes (M-CnT). The following membrane characteristics were examined: mechanical properties, morphological structure, porosity, elemental composition and functional groups, and surface hydrophilicity. The membrane's filtration performance was analyzed in terms of its ability to pass water (flux) and concentrate lactalbumin protein. The results showed that the changes in the membrane morphological structure were clearly visible in the SEM test, which exposed more open membrane pores after adding Pol and S-CnT/M-CnT additives. The mechanical properties of the membrane also increased, as indicated by the increase in the tensile strength from 12.1 MPa to 16.07 MPa. In general, it was found that the composition of the PVDF/Pol/S-CnT/NMP polymer solutions resulted in better filtration performance compared to the membranes made of only the PVDF/NMP polymer solution. [ABSTRACT FROM AUTHOR]

In the coffee industry, the use of natural coffee extracts with differentiated attributes is desirable to drive new product development. This study evaluates the impact of ultrafiltration membrane processing on the sensory, metabolic, and physicochemical attributes of four commercially available coffee extracts: cold brew, lightly roasted, freeze concentrated and evaporated standard. The sensory analysis revealed an increase in acidity in the permeate across all extracts, with the most significant profile changes observed in the lightly roasted evaporated and evaporated extracts, accompanied by an enhancement of fruity and floral attributes. Furthermore, the permeate showed reduced total dissolved solids, while the caffeine concentration increased. Metabolomic analysis highlighted key coffee-related metabolites like cinnamic and coumaric acids, explaining observed variations due to their passage through the membrane. Our findings emphasize the potential of permeate as a coffee-based ingredient for ready-to-drink products development, providing a unique coffee experience with organoleptic profiles distinct from traditional beverages. [Display omitted] • UF process improves sensory and metabolic characteristics of coffee extracts. • 75 metabolites and 42 sensory attributes were altered between feed and permeate. • Permeate holds potential as an ingredient for developing ready-to-drink products. [ABSTRACT FROM AUTHOR]

The presence of antibiotics in aquatic systems in recent years has become a global environmental and public health concern due to the appearance of strains resistant to these antibiotics. Oxytetracycline (OXT) is a high-impact antibiotic used for both human and veterinary consumption, and it is the second most used antibiotic in aquaculture in Chile. Based on the above, this problem is addressed using a linear polymer whose structure is composed of aromatic rings and quaternary ammonium groups, which will help enhance the removal capacity of this antibiotic. To obtain the polycation, a radical polymerization synthesis was carried out using (4-vinylbenzyl)-trimethylammonium chloride as the monomer. The polycation was characterized via Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). The removal studies were conducted under different experimental conditions such as pH levels (3.0, 5.0, 7.0, 8.0, and 11.0), ionic strength (0.0–0.50 mg L−1 of NaCl), polymer dose (0.25–25.5 mg), variation of the antibiotic concentration (1–100 mg L−1), and evaluation of the maximum retention capacity, as well as load and discharge studies. The antibiotic retention removal was higher than 80.0%. The antibiotic removal performance is greatly affected by the effect of pH, ionic strength, molar ratio, and/or OXT concentration, as these parameters directly affect the electrostatic interactions between the polymer and the antibiotics. The diafiltration technique was shown to be highly efficient for the removal of OXT, with maximum removal capacities of 1273, 966, and 778 mg OXT g−1 polycation. In conclusion, it can be said that coupling water-soluble polymers to the diafiltration technique is an excellent low-cost way to address the problem of antibiotics in aquatic systems.

Emerging antibiotic contaminants in water is a global problem because bacterial strains resistant to these antibiotics arise, risking human health. This study describes the use of poly[(4-vinylbenzyl) trimethylammonium chloride] and N-alkylated chitosan, two cationic polymers with different natures and structures to remove nalidixic acid. Both contain ammonium salt as a functional group. One of them is a synthetic polymer, and the other is a modified artificial polymer. The removal of the antibiotic was investigated under various experimental conditions (pH, ionic strength, and antibiotic concentration) using the technique of liquid-phase polymer-based retention (LPR). In addition, a stochastic algorithm provided by Fukui’s functions is used. It was shown that alkylated N-chitosan presents 65.0% removal at pH 7, while poly[(4-vinylbenzyl)trimethylammonium chloride] removes 75.0% at pH 9. The interaction mechanisms that predominate the removal processes are electrostatic interactions, π–π interactions, and hydrogen bonding. The polymers reached maximum retention capacities of 1605 mg g−1 for poly[(4-vinylbenzyl) trimethylammonium chloride] and 561 mg g−1 of antibiotic per gram for alkylated poly(N-chitosan). In conclusion, the presence of aromatic groups improves the capacity and polymer–antibiotic interactions.

Despite the high removal ability of the wastewater treatment technologies, research efforts have been limited to the relatively large-sized microplastics, leaving nanoplastics outside the studied size spectrum. This study aims to evaluate the process performance of MF and UF membranes for the removal of single and mixed solutions of polystyrene nanospheres (120 and 500 nm) and BSA. The process performance was evaluated in terms of the rejection coefficient, the normalized flux, and the permeability recovery. The fouling mechanism of these pollutants was studied, evaluating the effect of different membrane materials, membrane pore sizes, and nanoplastic sizes, as well as the synergetic effect of the mixture of foulants. This study was complemented by surface membrane characterization. Polystyrene nanospheres were successfully removed with all the membranes studied, except for the MF membrane that obtained PS 120 nm rejection coefficients of 26%. Single nanoplastic particles were deposited in UF membranes creating a pore blocking and cake layer formation, whilst the nanoplastics of 120 nm were accumulated inside the MF membrane creating an internal pore blocking. In mixed solutions, the BSA acted in two different ways: (i) as a stabilizer, hindering the deposition of nanoplastics and (ii) as a main foulant that caused a substantial flux reduction.

Treatment of textile wastewater has been a matter of considerable interest because of the potential toxicity, colloidal stability, and deformable nature of dyes. Herein, a novel polyaniline (PANI)/polyvinylidene fluoride (PVDF) hybrid membrane is developed to remove textile wastewater dyes. The hybrid membrane's contact angle decreases by increasing the concentration of polyaniline in the PVDF matrix, enhancing the hybrid membrane's hydrophilicity. Membrane properties, including porosity, antifouling property, solvent content, and pure water flux, are improved in the hybrid membrane compared with neat PVDF membranes. The purified water flux is enhanced from 28 to 47 L m−2 h, which indicates the impact of PANI on the hydrophilicity of the hybrid membranes. Among the hybrid membranes, 3P exhibits 85% dye rejection at 0.1 MPa operating pressure. Hence, the incorporation of PANI in the PVDF matrix is proposed to enhance the hybrid membrane's dye rejection and antifouling properties. [ABSTRACT FROM AUTHOR]

• The effectiveness of tannin and calcium residues in microalgae UF antifouling strategies was investigated. • Steel industry residues enhance filtration over commercial coagulants. • Bag filter powder reduces fouling resistance by 30 % • Steel industry residues altered clake morphology, impacting cake layer structure and flow reversibility. This study aimed to assess the impact of various coagulants and alternative sources of Ca2+ as pre-treatment on a microalgae suspension undergoing ultrafiltration. Two commercial coagulants, namely aluminum polychloride (PAC) and Tanfloc SL, were compared against two calcium-rich residues from the steel industry: blast oxygen furnace slag and bag filter powder. The filterability of the samples was assessed through permeate flux measurement, analysis of added membrane resistances, and examination of fouling formation mechanisms. Additionally, the characteristics of the formed deposit, including membrane surface morphologies and functional groups, were characterized. Coagulation-flocculation significantly influenced floc characteristics, thereby impacting the filterability of the microalgae samples. Both aluminum polychloride and Tanfloc demonstrated a slight reduction in flux decay, except at 40 mg.L-1 doses, which notably increased normalized final flux. However, Tanfloc exhibited poorer performance compared to coagulated filtrations with calcium-rich residues in terms of fouling. Bag filter powder displayed a 30 % lower fouling resistance than the microalgae suspension without a coagulant. The predominant mechanism observed in fouling formation was attributed to cake layer formation, with the observed fouling being mostly reversible. [ABSTRACT FROM AUTHOR]

The objects of the study were the Doy Chemical hollow-fiber ultrafiltration membranes which were use for preparation of make-up water for the Novocherkasskaya Regional Thermal Power Plant (RTPP).We tried out a possibility of applying the X-ray fluorescence spectrometry to study the condition of the spent non-recoverable ultrafiltration membranes in order to identify the causes of their irreversible destruction. The ARL Quant’X X-ray fluorescence energy dispersive spectrometer of Thermo Scientific (USA) was used in the study.Thin cuts of the Doy Chemical hollow-fiber ultrafiltration membranes were used in the experiments, which had worked for more than three years in the field conditions of the feed water of the Don River, Russia.The analysis of the obtained samples spectra allowed us to assume that the membranes were irreversibly contaminated by iron bacteria. Basing on the conclusions made during the analysis of X-ray fluorescence spectra we developed and tested in field conditions one of the optimization variants for technological pretreatment scheme. This scheme enables a significant increase in the service life of ultrafiltration membranes, even when the feed water is heavily contaminated by bacteria. Field tests of the modernized technology were carried out at Novocherkasskaya RTPP during 2016-2018 and showed a significant increase in the service life of the membrane modules. At the same time, the quality of the filtrate, productivity and pressure drops at the cascades of ultrafiltration units fully corresponded to the normative values even in conditions of deteriorated quality of the feed river water.It has been proved that aggressive regeneration of ultrafiltration membranes that have worked for a long time under the conditions of feed water having increased values of the total microbial number and high values of permanganate oxidation does not allow one to restore their initial state. In this case the main cause of ultrafiltration membranes contamination is iron, which is present in colloidal and bacterial forms in the pores and on the membranes surfaces. In the conditions of the Novocherkasskaya RTPP, in addition to timely flushing and chemical regeneration of ultrafiltration membranes, the necessity of organizing a preliminary treatment of the feed water with reagents having a prolonged bactericidal effect is accepted.

The fly ash based carbon nanotubes (CNTs) were used to modify polymeric ultrafiltration membranes for protein separation. The phase inversion method was used to synthesize asymmetric polysulfone (PSF) membranes using 1-methyl-2-pyrrolidone (NMP) as solvent. Polyethylene glycol (PEG) and synthesized fly ash CNTs with different proportions were used as pore former and additive, respectively. The membranes' functional, morphological, and permeation-based characterizations were conducted by using different characterization techniques, namely FTIR, AFM, FESEM, TGA, and water flux analysis. Liquid-liquid displacement porosimetry (LLDP) was used to demonstrate the membranes' pore size distribution. Separation efficiency, as well as the antifouling effect of the modified membranes, was perceived with the help of the model protein bovine serum albumin (BSA). The modified membranes showed improved hydrophilicity as the SWCA decreases from 73.4° to 46.2°. The AFM analysis shows that the surface roughness of the membranes decreases from 30.07 (CM0) to 12.05 (CM9) confirming positive antifouling nature. The maximum flux recovery ratio of 91.99% and BSA rejection of 84.11% were obtained with improved thermal stability as shown by the TGA analysis.

The application of separation technology using ultrafiltration/nanofiltration membranes for protein purification and concentration has grown rapidly in the last decade. Innovations to synthesize membranes with properties and performance that suit the characteristics of the feed solution have been and will keep developing. This study aims to examine the strategies to improve the performance of the Polyvinylidene Fluoride (PVDF) membrane for lactalbumin protein isolation. The PVDF polymer membrane was modified by adding Poloxamer 188 (Po1) copolymer and a combination of two types of nanocarbons, i.e., single-walled carbon nanotubes (S-CnT) and multi-walled carbon nanotubes (M-CnT). The following membrane characteristics were examined: mechanical properties, morphological structure, porosity, elemental composition and functional groups, and surface hydrophilicity. The membrane’s filtration performance was analyzed in terms of its ability to pass water (flux) and concentrate lactalbumin protein. The results showed that the changes in the membrane morphological structure were clearly visible in the SEM test, which exposed more open membrane pores after adding Pol and S-CnT/M-CnT additives. The mechanical properties of the membrane also increased, as indicated by the increase in the tensile strength from 12.1 MPa to 16.07 MPa. In general, it was found that the composition of the PVDF/Pol/S-CnT/NMP polymer solutions resulted in better filtration performance compared to the membranes made of only the PVDF/NMP polymer solution.

The application of nanocomposite materials in membrane bioreactors (MBRs) is attractive because of their great potential to enhance the filtration performance and antifouling. This study modified polyvinylidene fluoride (PVDF) ultrafiltration membranes using graphene oxide (GO) and sulfonation GO (SGO). The antibacterial properties of nanocomposite membranes were tested using three Gram-negative bacterial species (Pantoea agglomerans, Escherichia coli, and Pseudomonas graminis). The results showed that PVDF-GO and PVDF-SGO ultrafiltration (UF) membranes had significantly nontoxic properties (>95% , significance at p<0.0001), indicating that it was innocuous to bacterial growth. On the other hand, the nanoparticles (NPs) (GO and SGO) had approximately 50% antibacterial activity based on the viability tests, disc diffusion, and TEM analysis. The performance of membranes was examined using a pure water prermeabilty flux test. The water flux of the PVDF-SGO membrane (720 Lm−2 h−1) significantly increased compared with that of the GO membrane (428 Lm−2 h−1). Furthermore, the PVDF-SGO membrane had a 65.2% removal of methylene blue (MB), indicating that the SGO incorporated in the membrane enhanced the absorption capacity of heterocyclic aromatic compounds such as MB. The nanocomposite membranes (PVDF-GO and PVDF-SGO) are more sustainable than the PVDF membrane and are promising materials for MBRs because they have higher permeability and absorption capacity, and re harmless to bacterial activity. [ABSTRACT FROM AUTHOR]

Commercially available ultrafiltration membranes were coated with cellulose nanofibers (CNFs) produced from softwood pulp by a two-step process: a non-derivatizing DES treatment and a simple mechanical treatment (high-speed homogenization and sonification). The CNFs coating aimed at enhancement of the removal of methylene blue (MB) from water and was investigated at different concentrations of the coating, quantified in grams of CNFs per square meter of the membrane (1.3, 6.5, 13, and 19.5 g/m2). The pure water permeability (PWP) was unaffected up to the concentration of 6.5 g/m2 but the dye retention increased approximately 2.5-fold. Even higher improvement of MB removal, about 4-fold, was observed when 19.5 g/m2 were used, however, the pure water permeability also decreased by about 30%. In addition, it was proved that the coating can be removed and created again several times which shows that the concept could be used to improve the retention of organic compounds when high permeability membranes are used.

Surface segregation in blended polymer films has attracted much interest in fundamental research as well as for practical applications. A variety of methodologies have been proposed for controlling surface segregation. They often require long annealing times, however, to achieve thermodynamic equilibrium. Here, a strategy and proof‐of‐principle experiments are described to control surface segregation of thin block‐copolymer (BCP) layers on top of a homopolymer in a single casting step from blended BCP/homopolymer solutions. The surface coverage by the minor constituent BCP (2–10 wt%) is accomplished despite almost identical surface energies of BCP and homopolymer constituents. Immersing this casted solution into water for nonsolvent induced phase separation (NIPS), a nonequilibrium process, affords solidified bilayer ultrafiltration membranes composed of a thin porous surface layer of self‐assembled BCP atop an asymmetric porous homopolymer substructure. Key to successful BCP surface segregation is the choice of a binary solvent system based on careful considerations of solvent surface energies and polymer‐solvent interaction parameters. Furthermore, stabilizing the BCP micellar structure by a divalent metal additive is also essential. The approach provides a cost‐effective method for fabricating bilayer‐type asymmetric ultrafiltration membranes with uniform BCP self‐assembly based selective top surface pore layers in a single casting step. [ABSTRACT FROM AUTHOR]

The pollutant composition of landfill leachate is complex, and pollutant concentrations change greatly. Moreover, landfill leachates can easily penetrate into the soil and eventually pollute the ground water, which can cause environmental pollution and threaten human health. At present, landfill leachate treatment technology is still not mature. In this paper, the A/O-MBR (Anoxic–Aerobic Membrane Bioreactor) process is proposed to treat landfill leachate. To increase the hydrophilicity of the membranes and reduce the pollution of the membranes, the self-made TiO2 nanoparticles were used to modify the ultrafiltration membranes (PVDF-2). Meanwhile, PVDF-2 composite membranes showed the best separation performance. The optimum operating parameters were determined by changing the concentration of the pollutants in the reactor and selecting the dissolved oxygen, pH, and hydraulic residence time. The results show that the optimum operating conditions of MBR are mixed liquor suspended solids (MLSS) = 3200 mg/L, DO = 1.5–2.5 mg/L in a nitrifying tank, DO = 0–0.5 mg/L in a denitrifying tank, pH = 7–8, and a hydraulic retention time (HRT) = 5 h. To reach the “Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants” (GB18918-2002), the effluent of the MBR system further enters into the RO system. This work presents an environmentally friendly synthesis of TiO2 nanoparticles and added into PVDF. The addition of self-made TiO2 in PVDF membrane has improved the antifouling performance significantly, which has the potential for the treatment of landfill leachate.

This manuscript is an overview of the versatile biopolymer materials alginic acid, carboxymethyl cellulose, and quaternized chitosan which contain different functional groups to remove hazardous inorganic species. These bioadsorbents are completely water-soluble and have a high versatility to achieve a higher sorption capacity and efficiency under different experimental conditions in combination with ultrafiltration membranes through the liquid-phase polymer-based retention (LPR) technique. In general, thesebioadsorbents are friendly with the environment and have a higher biodegradability compared with those more employed synthetic polymers. [ABSTRACT FROM AUTHOR]

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Membrane separation technology is one of the cost effective and most efficient technologies for treatment of wastewater from textile industry. However, development of membranes with better performance and thermal stability is still a highly challenging task. In this study, successful preparation of a novel thermally stable polyimide (PI) polymer was demonstrated using 2,4,6-trimethyl-1,3-phenylenediamine, 4,4′-diaminodiphenylmethane and 1,2,4,5-benzenetetracarboxylic dianhydride components. PI was selected as representative candidate because of its excellent thermal stability (decomposition temperature of 529 °C), as revealed by thermogravimetric analysis. Furthermore, PI polymer was used to fabricate ultrafiltration (UF) membrane by phase inversion process. This UF membrane is especially interesting as it allowed for almost complete penetration of monovalent (NaCl) and divalent (Na 2 SO 4) inorganic salts because of its molecular weight cut off of 9320 Da. Moreover, the membrane exhibited very good surface hydrophilicity with the water contact angle of 67.6°. This PI-based UF membrane was found to be substantially effective as it showed high pure-water and dye-permeation fluxes of 345.10 and 305.58 L m−2 h−1 at 0.1 MPa, respectively. Besides, the membrane exhibited a rejection of 98.65% toward the direct red 23 dye (100 ppm) at 0.1 MPa. Thus, this PI-based UF membrane is highly beneficial and acts as a potential candidate for dye removal from wastewater produced by textile industry. [ABSTRACT FROM AUTHOR]

Polyphenylsulfone/multiwalled carbon nanotubes/polyvinylpyrrolidone/1-methyl-2-pyrrolidone mixed matrix ultrafiltration flat-sheet membranes were fabricated via phase inversion process to inspect the heavy metals separation efficacy from aqueous media. Fabricated membranes cross-sectional morphological changes and the topographical alterations were assessed with Scanning electron microscopy (SEM) and atomic force microscopy (AFM). Particularly, MWCNTs assisted membranes exhibited better permeability ability as well as heavy metal removal enactment than virgin membrane. The dead-end filter unit was engaged in current research to examine the permeability and heavy metal removal competence of membranes. With the continuous enhancement of MWCNTs wt% in a polymer matrix, significant enhancement was observed with pure water flux study, from 41.69 L/m2 h to >185 L/m2 h as well as with the heavy metals separation study. Added additive MWCNTs can impact the pore sizes in membranes. The heavy metal separation results achieved, the membrane with 0.3 wt% of MWCNTs (PCNT-3) exhibited >98%, >76% and >72% for Pb2+, Hg2+ and Cd2+ ions, respectively. Overall, MWCNTs introduced PPSU membranes exposed best outcomes with heavy metals contained wastewater treatment. [ABSTRACT FROM AUTHOR]

Ultrafiltration membranes based on aromatic copolyamide, comprising 10% of units with sulfonate groups were produced. The possibility of their use as a matrix for the immobilization of ligands used in affinity chromatography: metal cations, amino acids, and dyes, is shown. The components of immobilization were copper(II) ions, histidine, lysine, and 3,6-diamino-10-methylacridine chloride. It was found that immobilization mainly occurs due to the electrostatic interaction of the corresponding functional groups of the component and copolyamide and is not accompanied by a decrease in the specific membrane productivity in water. The investigations of adsorption (under static conditions and ultrafiltration of protein solutions) were performed as well as mass transfer properties of modified membranes. The nature of the effect of the modification was revealed on the mass transfer characteristics of the obtained materials. For an unmodified membrane, the optimal combination of selectivity and specific productivity was realized at pH of the protein solution above its isoelectric point. Depending on the nature of the immobilized component, selectivity of 0.96–0.99 can be achieved at the pH below or equal to the isoelectric point of the protein. [ABSTRACT FROM AUTHOR]

BACKGROUND: Charged ultrafiltration membranes combined with optimal operating conditions can be used to enable monoclonal antibody purification. Positively charged ligands bound to the membrane surface can significantly contribute to the adsorption of negatively charged proteins and enhance the purification process. RESULTS: In this work, commercially available 500 kDa polyethersulfone ultrafiltration membranes were modified by sulfonation, followed by deposition of polyethyleneimine (PEI) and crosslinking with butanedioldiglycidylether. Polymer molecules of 2 and 10 kDa were used to evaluate how polymer size influences the fractionation of a harvested Chinese hamster ovary cell culture fluid containing a monoclonal antibody by ultrafiltration at different operational pH values. The precursor and modified membranes were analyzed by X‐ray photoelectron spectroscopy, which confirmed the successful modification of membranes. Nitrogen analysis showed the presence of amine groups, clearly confirming immobilization of PEI onto the membrane surface. When 10 kDa PEI is chosen for membrane modification, the intensity of this signal increases, as predicted for a higher‐molecular‐weight polymer. Ultrafiltration performance indicators (fluxes, transmissions, yields) were determined and compared for the modified and precursor membranes, with the PEI‐derived membranes showing ability for pH modulation of selectivity. CONCLUSION: High purities were consistently observed at pH 9 owing to a simultaneous decrease in the transmission of soluble protein and increase in both IgG transmission and adsorptive capacity of the membranes. A single‐step process at pH 9 renders a permeate with an antibody purity of 96%, using a non‐crosslinked membrane modified with 10 kDa PEI. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A study on the chemical stability of anodic alumina membranes and their performance in long-term water and organic solvent permeation experiments is reported. Anodic alumina possesses high stability for both protonic and aprotonic organic solvents. However, serious degradation of the membrane occurs in pure water, leading to a drastic decrease of permeance (over 20% of the initial value after the passing of 0.250 m3/m2 of pure water). The drying of the membrane induces further permeance drop-off. The rate of membrane degradation strongly depends on the pH of the penetrant solution and increases in basic media. According to 27Al NMR and thermogravimetry results, the degradation of the membranes is associated with the dissolution of water-soluble [Al13O4(OH)24(H2O)12]7+ polyhydroxocomplexes and their further redeposition in the form of [Al(OH)4]−, resulting in channels blocking. This process intensifies in basic pH due to the high positive charge of the anodic alumina surface. An approach for improving anodic aluminum oxide stability towards dissolution in water by carbon CVD coating of the membrane walls is suggested.

Industrially, ultrafiltration (UF) membranes are produced through non-solvent induced phase separation (NIPS), but due to environmental hazards inherent to the NIPS process as well as the low surface porosity and fouling resistance of membranes produced via this method, an alternative route to UF membranes is desirable. This work presents the self-assembly of Pluronic block copolymers in the presence of water and a monomeric phase as a new technique for the preparation of UF membranes without the need for organic solvent or post-modification. Different compositions of block copolymer, water, and monomer were polymerized to obtain both hexagonal and lamellar mesostructures, as indicated by small angle X-ray scattering (SAXS) and cross-polarized light microscopy. As-synthesized membranes were found to have pore sizes in the range of 3–4 nm with a molecular weight cutoff of 1500 g/mol and displayed both excellent fouling resistance and high permeance of water, vastly outperforming a conventional NIPS UF membrane. Further, in contrast to NIPS, the proposed method provides flexibility in terms of both the final membrane chemistry and pore size. As such, it is a versatile approach that can be easily tailored to produce membranes for a wide range of applications including wastewater treatment and food processing. Image 1 • Block copolymer/water/oil mesophases can be used as templates for making membranes. • Membranes with ∼3–4 nm pore size can be made through mesophase-templating. • Mesophase-templated membranes have superior rejection compared to commercial ones. • Mesophase-templated membranes showed low flux decline in dead-end filtration. [ABSTRACT FROM AUTHOR]

In asymmetrical flow field-flow fractionation (AF4), similar to other separation techniques, mass recovery and overloading require special attention in order to obtain quantitative results. We conducted a systematic study with five globular proteins of different molecular weight (36.7–669 kDa) and isoelectric point (4.0–6.5), and ultrafiltration membranes that are commonly used in aqueous AF4, regenerated cellulose (RC) and polyethersulfone (PES). Phosphate-buffered saline (PBS) with ionic strength 0.15 M and pH 7.2 was used as the carrier liquid in this study. The actual molecular weight cutoff (MWCO) was found to be higher than the nominal value and varied between membranes of different chemistry but the same nominal MWCO. Adsorption on the membrane was found to be dependent on the membrane chemistry (RC had lower adsorption compared to PES), and independent of the protein standard for the examined proteins. On the other hand, the mass overloading effects (i.e., higher retention times, peak broadening, and fronting peaks) were significantly more pronounced for γ-globulin than for the other proteins. The overloading effects could be rationalized with the increase of the local viscosity close to the membrane, depending on the properties of the proteins, and we derived theoretical equations that related the dependency of the migration velocity on the protein concentration through this non-ideal viscosity effect. [ABSTRACT FROM AUTHOR]

Bacterial adhesion to surfaces is related to several factors, such as surface charge, surface energy, and substrate characteristics (leading to the formation of biofilms). Organisms are dominant in most environmental, industrial, and medical problems and processes that are of interest to microbiologists. Biofilm cells are at least 500 times more resistant to antibacterial agents compared to planktonic cells. The usage of ultrafiltration membranes is fast becoming popular for water treatment. Membrane lifetime and permeate flux are primarily affected by the phenomena of microbial accumulation and fouling at the membrane's surface. This review intends to understand the mechanism of membrane fouling by bacterial attachment on polymeric ultrafiltration membrane modified by natural antimicrobial polymers (chitosan) combined with powder activated carbon. Also, to guide future research on membrane water treatment processes, adhesion prediction using the extended Derjaguin-Landau-Verwey-Overbeek theory is discussed. [ABSTRACT FROM AUTHOR]

Formulas for ultrafiltration operating and geometric parameters that take into account the longitudinal diffusion of solute molecules in a solution under treatment have been derived based on differential equations of material balance. The effect of longitudinal diffusion on the concentration of solute molecules in the permeate and the retentate in comparison with plug flow and perfect mixing conditions has been evaluated. [ABSTRACT FROM AUTHOR]

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In this work, nanocrystalline cellulose (NCC)/polyvinylidene fluoride (PVDF) ultrafiltration composite membranes reinforced with graphene oxide (GO) were successfully prepared by the Loeb–Sourirajan phase inversion process. Firstly, the effects of mutual interactions between GO and NCC on membrane surface structure, morphology, and performance were investigated in detail. The existence of hydrogen bonds between GO and NCC in the membrane was confirmed by Fourier-transform infrared spectroscopy. The morphology of the membranes was observed by scanning electron microscopy. The water flux, bovine serum albumin rejection, and attenuate coefficient of the membranes were determined to investigate the filtration performance, and the filtration performance was hardly affected with addition of GO. The NCC/PVDF membrane modified with 1.0 wt% GO showed the highest tensile strength of 9.56 MPa, which was 58.01% higher than that of the unmodified membrane. Thermogravimetric analysis indicated that the blend membranes modified with GO had higher thermal stability compared with the unmodified NCC/PVDF membrane. When the NCC content was 0.5 wt% and the GO content was 1.0 wt% (the content of GO was based on the weight of PVDF), the optimized performance could be obtained due to the formation of hydrogen bonds between GO and NCC. [ABSTRACT FROM AUTHOR]

Removing lactose from buttermilk and other dairy products is a topical problem, as there is a significant increase in morbidity rates due to lactose intolerance. In many cases, milk and dairy products containing lactose can not be completely excluded from the diet. These products have a number of valuable components. There are several ways to remove lactose from milk or other dairy products. They are based on separation methods of processing and on the use of enzymes. Among the separation methods, membrane treatment, including diafiltration, is of particular importance. A technique of engineering calculation of cleaning an ultrafiltration buttermilk concentrate is suggested. As a solvent that reduces the concentration of lactose, a nanofiltrate permeate of buttermilk ultrafiltration is used. This method allows preserving the chemical composition of the concentrate with lactose effectively removed. Basing on the experimental data of membrane productivity and their selectivity for lactose, the main characteristics of diafiltration are calculated for various practical applications. For practical purposes, it is advisable to use a buttermilk permeate nanofiltrate using highly selective lactose membranes. Selectivity for salts should be minimal. When comparing the different diafiltration variants, the most suitable is a periodic method, with continuous dilution, and a continuous method with a crossflow and reverse flow of the nanofiltrate. The smallest аmount of a nanofiltrate is observed in the case of a continuous countercurrent. The time for diafiltration treatment depends on the membrane’s specific parameters, process operating parameters, and the selected lactose purification variant. The most cost-effective is the continuous variant with a countercurrent nanofiltrate. However, it can not be recommended because of the considerable duration of the process. The suggested technique for calculating diafiltration allows quick evaluation of possible options of purifying the product from lactose, and concludes which one is optimal.

The presence of antibiotics in aquatic systems in recent years has become a global environmental and public health concern due to the appearance of strains resistant to these antibiotics. Oxytetracycline (OXT) is a high-impact antibiotic used for both human and veterinary consumption, and it is the second most used antibiotic in aquaculture in Chile. Based on the above, this problem is addressed using a linear polymer whose structure is composed of aromatic rings and quaternary ammonium groups, which will help enhance the removal capacity of this antibiotic. To obtain the polycation, a radical polymerization synthesis was carried out using (4-vinylbenzyl)-trimethylammonium chloride as the monomer. The polycation was characterized via Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). The removal studies were conducted under different experimental conditions such as pH levels (3.0, 5.0, 7.0, 8.0, and 11.0), ionic strength (0.0-0.50 mg L -1 of NaCl), polymer dose (0.25-25.5 mg), variation of the antibiotic concentration (1-100 mg L -1 ), and evaluation of the maximum retention capacity, as well as load and discharge studies. The antibiotic retention removal was higher than 80.0%. The antibiotic removal performance is greatly affected by the effect of pH, ionic strength, molar ratio, and/or OXT concentration, as these parameters directly affect the electrostatic interactions between the polymer and the antibiotics. The diafiltration technique was shown to be highly efficient for the removal of OXT, with maximum removal capacities of 1273, 966, and 778 mg OXT g -1 polycation. In conclusion, it can be said that coupling water-soluble polymers to the diafiltration technique is an excellent low-cost way to address the problem of antibiotics in aquatic systems.

A novel polysulfone (PSf) nanocomposite ultrafiltration (UF) membrane using sulfonated graphene oxide (SGO) as additives was fabricated and investigated. SGO nanoparticles were chemically synthesized from graphene oxide (GO) by using sulfuric acid (H 2 SO 4 ) and were confirmed by Raman and Fourier transform infrared (FTIR) spectroscopy. The morphology of prepared membranes was characterized by scanning electron microscopy (SEM), energy dispersive x-ray (EDX) and atomic force microscopy (AFM). Results showed that adding small amount (less than 0.3 wt%) of SGO improved wettability, porosity and mean pore size of PSf/SGO membranes compared to the pristine PSf membrane and significantly enhanced the water flux of SGO incorporated PSf membranes. In UF performance, the nanocomposite membrane prepared by adding 1.5 w/w% SGO of PSf (designated as M1.5) showed the highest water flux result, which was 125% higher than the control PSf membrane (no SGO addition). Interestingly, there was no trade-off between water flux and bovine serum albumin (BSA) rejection, i.e more than 98% BSA rejection. The addition of SGO hydrophilic additives also showed better results in long-term BSA separation performance. The enhancement of hybrid membrane's properties was attributed to the hydrophilicity of sulfonic acid group ( SO 3 H) on the surface of SGO additive. This study suggested that the SGO nanoparticle is a promising candidate to modify the PSf UF membranes. [ABSTRACT FROM AUTHOR]

High permeability is one of the most important pursuits of separation membranes. In this work, high-performance ultrafiltration membranes are prepared by synergetically coupling nonsolvent-induced phase separation (NIPS) and selective swelling of a block copolymer, polysulfone- block -poly (ethylene glycol) (PSF- b -PEG). NIPS is used to prepare PSF- b -PEG membranes with a thin skin layer and a fingerlike sublayer. Subsequent selective swelling generates mesopores in the skin layer and enriches PEG blocks on the surface. Compared to the membranes without swelling, the swelling-treated membranes exhibit simultaneously upgraded permeability, hydrophilicity, and fouling resistance. For instance, the permeability of the membrane swollen in 50% acetic acid at 65 °C for 1 h is doubled compared to the pristine one while the rejection is only modestly reduced. Fouling resistance of the swelling-treated membranes is also improved, which is ascribed to the enrichment of PEG on the membrane surface. We demonstrate that the performances of the membranes can be tuned in a relatively wide range by tailoring the swelling conditions, such as swelling reagents, durations and temperatures. Because of the extreme simplicity and high efficiency, this selective swelling strategy is expected to be applicable in tuning the surface properties and improving performances of many other membranes. [ABSTRACT FROM AUTHOR]

Experiments on the preparation of sols and nanopowders of SiO2 based on hydrothermal solutions are performed. In order to achieve a result, processes of polycondensation of orthosilicic acid, ultrafiltration membrane concentration, and cryochemical vacuum sublimation are performed. The physicochemical characteristics of the sols and nanopowders of SiO2 are determined using a set of methods. In particular, it is shown that the diameters of the nanoparticles of SiO2 in the sols and nanopowders fall within the range of 5 to 100 nm. The possibility for the application of the obtained nanosilica as a modifying additive for the enhancement of the strength of concrete is justified. [ABSTRACT FROM AUTHOR]

ABSTRACT: Selectivity for monovalent ions is a very important feature of ion exchange membranes in view of a further expansion of the scope of electrodialysis (ED). An efficient one‐step chemical process to graft a thin polyaniline (PANI) layer on the surface and pores of an ultrafiltration (UF) membrane is reported. The existence of a PANI layer on such modified UF membrane was confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy images. These membranes were extensively characterized by studying their properties such as water uptake, ion‐exchange capacity, contact angle, and performance in diffusion dialysis. ED experiments were conducted by comparing desalting of sodium chloride and magnesium chloride solutions. During the desalting procedure, the driving force has two contributions, the electrical field and the salinity‐gradient. Initially, transport of ions by the electrical field is dominant, while at the end of the experiment, diffusion dialysis by the salinity gradient plays a larger role in ion transport. The presence of PANI can hinder Mg2+ transport from the concentrate to the diluate compartment because of the electrostatic effect, while there is no obvious effect on Na+ ions. The ability of such a surface modification layer to improve the membrane selectivity for Na+/Mg2+ was confirmed by means of ED in a mixed solution. The flux of Na+ was slightly increased to 13.21 × 10−8 mol/L/min while the flux of Mg2+ was reduced to 3.32 × 10−8 mol/L/min, so that the permselectivity is almost doubled. The protonation reaction of the PANI layer creates positive charges, thus leading to an electrical repulsion barrier, which may reduce the penetration of divalent cations with respect to monovalent ions. Polyacrylonitrile‐based UF membranes with different molecular cutoff was used to determine the influence of the permselectivity. Results showed that the membrane permselectivity of smaller molecular cutoff UF membranes is higher. It can be concluded that this method is suitable for preparing membranes based on UF membranes for efficient separation of monovalent ions by electro‐driven separation techniques. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45692. [ABSTRACT FROM AUTHOR]

Ultrafiltration (UF) membranes were prepared from poly(vinyl chloride) (PVC) as main polymer, poly(vinyl pyrrolidone) (PVP) as additive, and 1‐methyl‐2‐pyrrolidone (NMP) as solvent using Design Expert software for designing the experiments. The membranes were characterized by SEM, contact angle measurement, and atomic force microscopy. The performance of UF membranes was evaluated by pure water flux (PWF) and blue indigo dye particle rejection. In addition, the molecular weight cutoff of UF membranes was determined by poly(ethylene glycol) (PEG) rejection. The UF membranes were used as substrates for fabrication of polyamide thin film composite (TFC) reverse osmosis (RO) membranes. The results showed that the model had high reliability for prediction of PWF of UF membranes. Also, increment in PVC concentration caused reduction of PWF. Moreover, at constant PVC concentration and if the concentrations of PVC was lower than 10 wt %, the PWF reduced by increasing the concentration of PVP. However, at PVC concentration higher than 11 wt %, increment in PVP concentration showed increment and reduction of PWF. The PEG rejection results showed that the prepared membranes had UF membranes properties. Finally, the NaCl rejection tests of RO membranes by PVC as substrates indicated that the performance of RO membranes were lower than commercial membranes. [ABSTRACT FROM AUTHOR]

To reveal the mechanisms of the influence of Ca2+ on membrane fouling with humic acid (HA), the adhesion forces of HA with both other HA molecules and the membrane, the HA fouling layer structure, HA fouling experiments, and the HA rejections at a wide range of Ca2+ dosages were investigated. The results indicated that the effect of Ca2+ on HA fouling can be divided into three stages. At lower ionic strength (IS) of CaCl2, the change in electrostatic forces is the main factor in controlling HA fouling behavior; i.e., increasing Ca2+ dosages resulted in more serious membrane fouling. When the IS of CaCl2 reached 10 mM, HA aggregates became the dominant factor in the fouling process, which could result in a porous fouling layer accompanied by less membrane fouling. Interestingly, much weaker membrane fouling was observed when the IS increased to 100 mM and the HA rejection began to decline. This was because a stronger hydration repulsion force was generated, which could weaken the compactness of the fouling layer and the adhesion forces of HA with both the membrane and HA, while enabling smaller-sized HA to pass more easily into the permeate, which led to less membrane fouling and a lower HA rejection. [ABSTRACT FROM AUTHOR]

In this work, graphene oxide (GO) was combined with polyethersulfone (PES) to form mixed matrix membranes (MMMs) for ultrafiltration of aqueous solutions. Also, the effect of adding various pore formers (poly(vinylpyrrolidinone (PVP), reverse triblock Pluronic (P31R1), and poloxamine Tetronic (T904)) to the dope solution was investigated. The prepared MMMs were characterised using various techniques, including Fourier-transform infrared spectroscopy, scanning electron microscopy and atomic force microscopy. It was found that the incorporation of 0.5 wt% of GO increased the flux from 2 to 13 L m −2 h −1 (LMH) and the rejection of bovine serum albumin (BSA) from 89.2 to 97% compared to benchmark PES membranes. SEM analysis revealed the increased pore size and porosity of the GO modified membranes, which contributed to the increased flux. The addition of pore formers further increased the flux compared to pure PES and also displayed synergistic effects with GO. The combination of T904 with 0.3 wt% GO increased the water flux significantly from 2 to 245 LMH and increased the rejection of acridine orange (from 40.5 to 48.4%) and BSA (from 89.6 to 93.3%), respectively. Also, fouling properties of the membranes were investigated with the parameters: flux recovery ratio ( FRR ), total flux decline ratio ( R t ), reversible flux decline ratio ( R r ), and irreversible flux decline ratio ( R ir ), and improved anti-fouling properties were obtained with the addition of GO. This work shows the promise of GO as a performance-enhancing additive in MMMs for wastewater treatment. [ABSTRACT FROM AUTHOR]

In a polymer-flooding wastewater treatment process, physically irreversible fouling of ultrafiltration (UF) membranes is severe and inevitable. Particularly, anionic polyacrylamide (APAM) aggravated flux loss is a challenge in flux recovery. Chemical cleaning procedures for polyvinylidene fluoride (PVDF) UF membranes fouled by polymers (e.g., APAM) were designed by investigating their cleaning efficiency, synergistic effect and molecular interactions based on the molecular mechanisms of polymeric fouling. The cleaning efficiency and foulant–foulant intermolecular interactions indicated that the destruction of the hydrogen-bonded network, egg-box shaped gel network, and interpenetrating polymer network using sodium hypochlorite (NaClO), ethylenediaminetetraacetic acid (EDTA) and dodecyl trimethyl ammonium chloride (DTAC) solutions, respectively, led to significant flux recovery. The synergistic relationships between the two types of cleaning reagents were different in the mixed solutions and sequential procedures. In addition, oil emulsions facilitated the removal of APAM and slowed the flux loss. Finally, the flux recoveries and operational aspects in the pilot-scale UF experiments indicated that integration of the tested chemical cleaning procedures can efficiently remove membrane foulants and significantly restore membrane flux during polymer-flooding wastewater treatment of UF processes. These results are promising for controlling membrane fouling due to polymeric foulants. [ABSTRACT FROM AUTHOR]