Effects of coagulation bath temperature and polyvinylpyrrolidone content on flat sheet asymmetric polyethersulfone membranes

In this study, effects of coagulation bath temperature (CBT) and polyvinylpyrrolidone (PVP K15) concentration as a pore former hydrophilic additive on morphology and performance of asymmetric polyethersulfone (PES) membranes were investigated. The membranes were prepared from a PES/ethanol/NMP system via phase inversion induced by immersion precipitation in a water coagulation bath. The morphology of prepared membranes was studied by scanning electron microscopy (SEM), contact angle measurements, and mechanical property measurements. Permeation performance of the prepared membranes was studied by separation experiments using pure water and bovine serum albumin (BSA) solution as feed. The obtained results indicate that addition of PVP in the casting solution enhances pure water permeation flux and BSA solution permeation flux while reducing protein rejection. Increasing CBT results in macrovoid formation in the membrane structure and increases the membrane permeability and decreases the protein rejection. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Preparation and characterization of asymmetric polyethersulfone nanofiltration membranes: The effects of polyvinylpyrrolidone molecular weights and concentrations

In this study, asymmetric flat‐sheet polyethersulfone (PES) nanofiltration (NF) membranes were prepared via immersion precipitation phase inversion with the addition of polyvinylpyrrolidone (PVP). The effects of PVP with the molecular weights (MW) from 17 to 1400 kDa and the concentration from 0 to 3.0 wt % on the morphologies and performances of PES membranes were systematically studied. The prepared membranes were characterized by SEM, AFM, ATR‐FTIR, contact angle, membrane porosity, the water flux, and the rejection measurement. The results indicated that the porosity and the hydrophilicity of PES NF membrane increased with increasing PVP concentration, and the hydrophilicity of PES NF membrane also improved with increasing PVP MW. The enhancements of the porosity and hydrophilicity resulted in the higher water flux of PES NF membrane. The rejection of Bordeaux S (MW 604.48 Da) for the prepared PES membrane was increased to above 90% with the low PVP concentration, but it turned to decrease remarkably when the PVP concentration reached to a critical value which related to PVP MW. It was concluded that the addition of a small amount of PVP could significantly increase the permeability of PES NF membrane and maintain its rejection of Bordeaux S above 90%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43769.     

Effects of PEG on Morphology and Permeation Properties of Polyethersulfone Membranes

Abstract

Flat sheet asymmetric polyethersulfone (PES) ultrafiltration (UF) membranes were prepared from a homogenous solution of PES via immersion precipitation in a water coagulation bath. The effect of the solvents (N-methyl-2-pyrrolidone (NMP) and N,N-dimethylformamide (DMF)) in preparation of the casting solution was studied. The effects of the molecular weight of polyethylene glycol (PEG) (400, 1500, and 6000 Da) on the morphology and the permeation properties of PES membranes were also investigated. Surface and cross-sectional morphology of the prepared membranes were studied by Scanning electron microscopy (SEM). The permeation performance of the prepared membranes was evaluated in terms of pure water flux (J_w), water content, porosity, hydraulic permeability, protein solution flux, and protein rejection. A solution of human serum albumin (HSA, Mw = 66,000 Da) was used as feed to study the permeation properties of the prepared membranes. Increasing molecular weight of PEG additives from 400 to 6000 Da enhances pure water permeation flux and HSA solution permeation flux while it reduces the protein rejection.     

Preparation and characterization of PES/CA microporous membranes via reverse thermally induced phase separation process

The blend polyethersulfone (PES)/cellulose acetate (CA) flat‐sheet microporous membranes were prepared by reverse thermally induced phase separation (RTIPS) process. The effects of CA content and coagulation bath temperature on membrane structures and properties were investigated in terms of membrane morphology, water contact angle, permeation performance, and mechanical properties. The cloud point results indicated that the cloud point decreased with the increasing content of CA. When the coagulation bath temperature was lower than the cloud point, the membrane formation process underwent nonsolvent induced phase separation (NIPS) process and dense skin layer and finger‐like structure were formed in membranes. These membranes had lower pure water flux and poor mechanical properties. But when the coagulation bath temperature was higher than the cloud point, the membrane formation process underwent RTIPS process. The porous top surface as well as porous cross‐section of the membranes were formed. Therefore, high pure water flux and good mechanical properties were obtained. The contact angles results indicated that the hydrophilicity of the prepared membranes improved obviously with the addition of CA. When the content of CA was 0.5 wt% and the membrane formation temperature was 323K, the PES/CA microporous membrane which was prepared via the RTIPS process displayed a optimal permeability of the pure water flux of 816 L m^?2 h^?1 and the BSA rejection rate of 49.5%, which showed an increase of 48.9% and 23.6% than that of pure PES membrane, respectively. Moreover, the mechanical strengths of the membranes obtained by RTIPS process were better than those membranes prepared by NIPS process. POLYM. ENG. SCI., 58:180–191, 2018. © 2017 Society of Plastics Engineers     

Synthesis and characterization of polyethersulfone membranes

Phase inversion method was used to prepare polyethersulfone (PES) ultrafiltration (UF) membranes. Polyethylene glycol (PEG); N, N-dimethyl formamide (DMF) and water were utilized as pore-forming additive, solvent and non-solvent, respectively. Effects of PES and PEG concentrations in the casting solution, PEG molecular weight (MW) and coagulation bath temperature (CBT) on morphology of the prepared membranes were investigated. Taguchi experimental design was applied to run a minimum number of experiments. 18 membranes were synthesized and their permeation and rejection properties to pure water and human serum albumin (HSA) solution were studied. It was found out that increasing PEG concentration, PEG MW and CBT, accelerates diffusional exchange rate of solvent (DMF) and non-solvent (water) and consequently facilitates formation of macrovoids in the membrane structure. The results showed that, increasing PES concentration, however, slows down the demixing process. This prevents instantaneous growth of nucleuses in the membrane structure. Hence, a large number of small nucleuses are created and distributed throughout the polymer film and denser membranes are synthesized. A trade-off between water permeation and HSA rejection was involved, with membranes having higher water permeation exhibited lower HSA rejection, and vice versa. Hence, optimizing preparation variables to achieve high pure water permeation flux along with reasonable HSA rejection was inevitable. Analysis of variance (ANOVA) showed that all parameters have significant effects on the response (water flux and HSA rejection). However, CBT and PES concentration were more influential factors than PEG concentration and MW on the responses.     

Use of Sodium Alginate-Poly(vinyl pyrrolidone) Membranes for Pervaporation Separation of Acetone/Water Mixtures

Pervaporative separation of acetone from water at a concentration range of 0–100 wt% were studied using sodium alginate (NaAlg)/Poly vinyl pyrrolidone (PVP) membranes. Membranes were prepared in different ratios (w/w) (100/0, 95/5, 90/10, 85/15, 80/20, 75/25) of NaAlg/PVP by crosslinking with CaCl₂. Experimental studies were carried out to investigate the effects of the operating temperature, feed composition, and membrane thickness on the pervaporation performance. The optimum operating temperature, membrane thickness, NaAlg/PVP ratio, and feed composition were determined as 40°C, 70 µm, 75/25 (w/w), and 20 wt% acetone, respectively. The effect of PVP content in the membranes was investigated on pervaporation performance. The permeation rate was increased with increasing the PVP content; however, there was no appreciable change about the separation factor. The permeation rate and separation factor values were found to be in the range of 0.304–1.023 kg/m² h and 16–57, respectively. In addition, the sorption-diffusion properties of the alginate membranes were investigated at the operating temperature and the feed composition. It was found that the sorption selectivity was the dominant factor for the separation of acetone/water mixtures.     

聚乙烯吡咯烷酮对聚醚砜膜结构和性能的影响

以聚醚砜为膜材料,聚乙烯吡咯烷酮（PVP）为添加剂,N,N-二甲基乙酰胺为溶剂,采用相转化法制备了聚醚砜超滤膜。通过制膜液粘度、膜的孔隙率、表面接触角、机械性能以及对牛血清蛋白分离性能的测试和扫描电镜（SEM）对膜孔结构的观察,研究了PVP的添加量对聚醚砜制膜液粘度及其膜结构和性能的影响。结果表明,PVP的添加提高了膜的亲水性和制膜液的粘度,但膜的抗拉强度有所降低;膜的水通量随着PVP含量的增加先升高后降低,在5%时最大水通量是508.33L/（m^2·h）,而此时牛蛋白截留率最小为66.27%;SEM观察的结果是膜的断面上部形成指状孔结构,下部形成海绵状孔结构,当PVP含量为5%时膜有斜指状孔结构,且指状孔也逐渐延伸到膜的底部,其壁为稀疏的海绵状孔结构。     

Effect of additives concentration on performance of cellulose acetate and polyethersulfone blend membranes

Asymmetric micro porous membranes have been prepared successfully from blending of cellulose acetate (CA) and polyethersulfone (PES) by the phase inversion method with N, N-dimethylformamide (DMF) as solvent. Two additives were selected in this study, including polyethylene glycol 600 (PEG 600) and polyvinylpyrrolidone (PVP). The effects of concentration of additives on CA/PES blend membrane performance and cross-section morphology were investigated in detail. CA/PES membranes were compared with CA/PES/PEG and CA/PES/PVP membranes in the performance such as pure water flux, membrane resistance, porosity and cross-section morphology. The resulting blend membranes were also carried out the rejection and permeate flux of Egg Albumin (EA) proteins with molecular weight of 45 Da. The membranes thus obtained with an additive concentration of 5 wt% of both PEG and PVP exhibited superior properties than the 80/20% blend composition of CA and PES membranes. The permeate flux of protein was increased from 44 to 134 lm² h with increase in concentrations of both PVP and PEG in 80/20% blend composition of CA and PES membranes. Cross-sectional images from scanning electron microscopy showed larger macropores in the bottom layer of the membranes with increasing additives content. Observations from scanning electron microscopy provided qualitative evidence for the trends obtained for permeability and porosity results.     

Polyethersulfone-polyvinylpyrrolidone composite membranes:Effects of polyvinylpyrrolidone content and polydopamine coating on membrane morphology,structure and performances

Hydrophilic modification is a promising method to inhibit fouling formation on ultrafiltration membrane.In this work,different mass concentrations (1％-16％) of hydrophilic polyvinylpyrrolidone were incorpo-rated into polyethersulfone (PES) membranes fabricated by none-solvent induced phase separation.Then,polydopamine (PDA) coating on the surface of prepared membrane was carried out at pH 8.5.The mor-phology and structure,surface hydrophilicity,permeation flux,BSA rejection,antifouling and stability performances of PES and PDA/PES modified membranes were investigated in detail.The results indicated that PDA was successfully attached onto the membranes.Membrane hydrophilicity was evaluated by water contact angle measurement.The contact angles of modified membranes reduced remarkably,sug-gesting that the membrane hydrophilicities were significantly increased.The results of filtration tests,which were done by dead-end filtration of bovine serum albumin solution,showed that the properties of permeability and fouling resistance were obviously improved by PDA modification.When polyvinylpyrrolidone mass content reached 10％,flux recovery ratio of modified membrane was up to 91.23％,and its BSA rejection were over 70％.The results of stability tests showed that the modified mem-branes had good mechanical stability and chemical stability.This facile fabrication procedure and out-standing performances suggested that the modified membranes had a potential in treating fouling.     

Development of novel surface modified phase inversion membranes having hydrophobic surface-modifying macromolecule (nSMM) for vacuum membrane distillation

Eleven PES membranes, into which newly synthesized surface-modifying macromolecule (nSMM) was incorporated, were prepared by using the ‘phase inversion technique’ with different preparation conditions to find the effects of membrane casting parameters on the characteristics and performances of the surface modified PES membranes. The membranes so prepared were characterized by solute separation data from ultrafiltration experiments. The results showed that the mean pore size as well as the surface hydrophobicity increased with an increase in evaporation time for the casting solution blended with nSMM (without PVP). When PVP was added into the casting solution, the mean pore size as well as the contact angle decreased while the pure water permeation flux increased. The surface hydrophobicity decreased with an increase in gelation bath temperature.Four membranes were further prepared and subjected to vacuum membrane distillation (VMD). They were characterized by different analytical instruments and pure water permeation test before being used to VMD. The results showed that a distinctive surface layer was formed in nSMM blended PES membranes. It was also found that nSMM blended PES membranes were sufficiently hydrophobic and porous to be used for the separation of an ethanol/water mixture.     

Zeolite 4A-Incorporated Polymeric Membranes for Pervaporation Separation of Methanol–Methyl Acetate Mixtures

Zeolite 4A-incorporated poly(vinyl alcohol)/poly(vinyl pyrrolidone) (PVA/PVP) membranes were prepared for pervaporation separation of methanol/methyl acetate mixtures. These membranes were characterized by Infrared spectroscopy, X-ray diffraction and Scanning electron microscopy. The results showed that crystallinity of the membrane decreased with the increase of zeolite 4A content. The effect of zeolite loading, feed composition and temperature on the membrane separation performance were discussed in detail. With the increase of zeolite 4A content, permeation flux increased continuously, but separation factor first increased and then decreased. The addition of 2.5 wt% zeolite 4A in the polymer membrane improved the separation factor from 12.9 (for PVA/PVP membrane) to the maximum value of 34.4 for 20 wt% methanol in feed at 45 °C. The separation factor decreased with increasing feed temperature, however, the flux increased with increasing feed temperature. Zeolite 4A-incorporated PVA/PVP membranes provide an effective method for the separation of methanol/methyl acetate azeotropic mixtures.     

Preparation of modified polyethersulfone membranes using variation in coagulation bath temperature and addition of hydrophilic surfactant

In this study, novel asymmetric polyethersulfone membranes were prepared from PES/PEG/Tween-20/NMP system via immersion precipitation. Pure water was used as gelation media. Simultaneous effects of variation in coagulation bath temperature (CBT) and addition of Tween-20 on morphology, wettabiliy, pure water permeation flux (PWF) and bovine serum albumin (BSA) rejection of the prepared membranes were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle measuring instrument and experimental set up. The obtained results indicate that the small addition of surfactants in the casting solution along with using the lowest level of CBT increases hydrophilicity of the PES membranes. Also it was found out that addition of Tween-20 in the casting solution along with increasing the CBT incites the formation of the bigger pores on the top surface and results in the formation of membranes with higher porosity in the sublayer.     

Effect of polyethylene glycol molecular weights and concentrations on polyethersulfone hollow fiber ultrafiltration membranes

Polyethersulfone (PES) hollow‐fiber membranes were fabricated using poly(ethyleneglycol) (PEG) with different molecular weights (MW = PEG200, PEG600, PEG2000, PEG6000, and PEG10000) and poly(vinyl pyrrolidone) PVP40000 as additives and N‐methyl‐2‐pyrrolidone (NMP) as a solvent. Asymmetric hollow‐fiber membranes were spun by a wet phase‐inversion method from 25 wt % solids of 20 : 5 : 75 (weight ratio) PES/PEG/NMP or 18 : 7 : 75 of PES/(PEG600 + PVP40000)/NMP solutions, whereas both the bore fluid and the external coagulant were water. Effects of PEG molecular weights and PEG600 concentrations in the dope solution on separation properties, morphology, and mechanical properties of PES hollow‐fiber membranes were investigated. The membrane structures of PES hollow‐fiber membranes including cross section, external surface, and internal surface were characterized by scanning electron microscopy and the mechanical properties of PES hollow‐fiber membranes were discussed. Bovine serum albumin (BSA, MW 67,000), chicken egg albumin (CEA, MW 45,000), and lysozyme (MW 14,400) were used for the measurement of rejection. It was found that with an increase of PEG molecular weights from 200 to 10,000 in the dope solution, membrane structures were changed from double‐layer fingerlike structure to voids in the shape of spheres or ellipsoids; moreover, there were crack phenomena on the internal surfaces and external surfaces of PES hollow‐fiber membranes, pure water permeation fluxes increased from 22.0 to 64.0 L m^?2 h^?1 bar^?1, rejections of three protein for PES/PEG hollow‐fiber membranes were not significant, and changes in mechanical properties were decreased. Besides, with a decrease of PEG600 concentrations in the dope solution, permeation flux and elongation at break decreased, whereas the addition of PVP40000 in the dope solution resulted in more smooth surfaces (internal or external) of PES/(PEG600 + PVP40000) hollow‐fiber membranes than those of PES/PEG hollow‐fiber membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3398–3407, 2004     

Effect of PVP Molecular Weights on the Properties of PVDF-TiO2 Composite Membrane for Oily Wastewater Treatment Process

Polyvinylidene fluoride (PVDF) hollow fiber ultrafiltration membranes consisted of TiO₂ and different molecular weight (M_w) of polyvinylpyrrolidone (PVP) (i.e., 10, 24, 40, and 360 kDa) were prepared to treat synthesized oily wastewater. The membrane performances were characterized in terms of pure water flux, permeate flux, and oil rejection while their morphological properties were studied using SEM, AFM, and tensile tester. Results show that the PVDF-TiO₂ composite membrane prepared from PVP40k was the best performing membrane owing to its promising water flux (72.2 L/m².h) coupled with good rejection of oil (94%) when tested with 250 ppm oily solution under submerged condition. It is also found that with increasing PVP M_w, the membrane tended to exhibit higher PVP and protein rejection, greater mechanical strength, smaller porosity, and a smoother surface layer. Regarding the effect of pH, the permeate flux of the PVDF-PVP40k membrane was reported to increase with increasing pH from 4 to 7, followed by decrease when the pH was further increased to 10. Increasing oil concentration in the feed solution was reported to negatively affect the water flux of PVDF-PVP40k membrane, owing to the formation of thicker oil layer on the membrane surface which increased water transport resistance. A simple backflushing process on the other hand could retrieve approximately 60% of the membrane original flux without affecting the oil separation efficiency. Based on the findings, the PVDF-TiO₂ membrane prepared from PVP40k can be potentially considered for oily wastewater treatment process due to its good combination of permeability and selectivity and reasonably high water recovery rate.     

Preparation of blend polyethersulfone/cellulose acetate/polyethylene glycol asymmetric membranes for oil–water separation

Blend PES/CA hydrophilic membranes were prepared via a phase-inversion process for oil–water separation. PEG-400 was introduced into the polymer solution in order to enhance phase-inversion and produce high permeability membranes. A gas permeation test was conducted to estimate mean pore size and surface porosity of the membranes. The membranes were characterized in terms of morphology, overall porosity, water contact angle, water flux and hydraulic resistance. A cross-flow separation system was used to evaluate oil–water separation performance of the membranes. From FESEM examination, the prepared PES/CA membrane presented thinner outer skin layer, higher surface porosity with larger pore sizes. The outer surface water contact angle of the prepared membrane significantly decreased when CA was added into the polymer solution. The higher water flux of the PES/CA membrane was related to the higher hydrophilicity and larger pore sizes of the membrane. From oil–water separation test, the PES/CA membrane showed stable oil rejection of 88 % and water flux of 27 l/m² s after 150 min of the operation. In conclusion, by controlling fabrication parameters a developed membrane structure with high hydrophilicity, high surface porosity and low resistance can be achieved to improve oil rejection and water productivity.     

聚间苯二甲酰间苯二胺平板膜的制备及其性能研究

以聚间苯二甲酰间苯二胺（PMIA）为制膜原料,氯化锂（LiCl）、聚乙二醇（PEG-400）和聚乙烯吡咯烷酮（PVP）为添加剂,通过非溶剂诱导相转化法制备了PMIA平板膜,系统考察了聚合物浓度、添加剂种类和含量对PMIA膜结构和性能的影响。结果表明,聚合物浓度和LiCl含量增加,铸膜液黏度增大,导致膜孔径减小,纯水通量降低。而PEG含量的增加,使得聚合物链呈现舒展状态,膜孔径增大,纯水通量升高,亲水性增强。随着PVP含量的增加,膜的纯水通量先升高后降低,膜的亲水性变差。当PMIA的质量分数为9%,LiCl的质量分数为2.8%,PVP的质量分数为1.2%时,膜的纯水通量高达1421.55 L·m^-2·h^-1·bar^-1,对牛血清蛋白（BSA）的截留率为80%,展现出较高的渗透性,为制备高性能膜材料提供了新的思路。     

聚间苯二甲酰间苯二胺平板膜的制备及其性能研究

以聚间苯二甲酰间苯二胺（PMIA）为制膜原料,氯化锂（LiCl）、聚乙二醇（PEG-400）和聚乙烯吡咯烷酮（PVP）为添加剂,通过非溶剂诱导相转化法制备了PMIA平板膜,系统考察了聚合物浓度、添加剂种类和含量对PMIA膜结构和性能的影响。结果表明,聚合物浓度和LiCl含量增加,铸膜液黏度增大,导致膜孔径减小,纯水通量降低。而PEG含量的增加,使得聚合物链呈现舒展状态,膜孔径增大,纯水通量升高,亲水性增强。随着PVP含量的增加,膜的纯水通量先升高后降低,膜的亲水性变差。当PMIA的质量分数为9%,LiCl的质量分数为2.8%,PVP的质量分数为1.2%时,膜的纯水通量高达1421.55 L·m^-2·h^-1·bar^-1,对牛血清蛋白（BSA）的截留率为80%,展现出较高的渗透性,为制备高性能膜材料提供了新的思路。     

Improvement of permeation performance of polyethersulfone (PES) ultrafiltration membranes via addition of Tween‐20

In this study, effects of Tween‐20 (polyoxyethylene sorbitan monolaurate) as a variable surfactant additive on morphology, permeation performance and antifouling properties of asymmetric polyethersulfone (PES) membranes were investigated. The membranes prepared from PES/polyethylene glycol (PEG)/N,N‐dimethylformamide (DMF) system via phase inversion induced by immersion precipitation in water coagulation bath. The membranes performances were evaluated using ultrafiltration (UF) experiments. The scanning electron microscope and atomic force microscopy analysis were performed to investigate the membrane morphology. The obtained results indicate that by increasing the concentration of Tween‐20, the membrane morphology changes slowly from thin finger‐like structure with spongy structure to long and wide finger‐like structure with some macrovoids. Addition of surfactant to the casting solution increases the porosity of the membrane sublayer. It was found out that the rejection ratio of Bovine serum albumin (BSA) decreases, while the flux recovery ratio remarkably increases and the degree of irreversible fouling decreases. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A melamine-based covalent organic framework nanomaterial as a nanofiller in polyethersulfone mixed matrix membranes to improve separation and antifouling performance

This research reported developing a polyethersulfone (PES) membrane using covalent organic frameworks (COFs) nanoparticle with a mean dimension of 30 nm. The SNW-1 (Schiff-based network) COF was synthesized using precursors of melamine and terephthalic acid and then characterized by XRD, SEM, TEM, and FTIR analyses. The influence of different loadings of the COF was evaluated on the permeability, antifouling behavior and dye/salt rejection. The addition of SNW-1 caused a reduction in surface roughness and an improvement in hydrophilicity of the nanocomposite membranes, which improved their flux and fouling resistance considerably. The improvement of water flux, 2.6 times, was observed by adding 0.5 wt% COF to the membrane matrix. The 0.5 wt% COF membrane presented the best water permeability, 38.9 L/m² h bar BSA solution flux, dye rejection of 98.7% for Reactive Green 19 and 62.6% for Reactive yellow 39, 52.9% Na₂SO₄ and 24.5% NaCl salt rejections. Zeta potential and salt rejection trend indicated a negative surface charge on the nanocomposite membrane. Fouling experiments by BSA protein solution exhibited that the FRR reached 88.9% for 2 wt% COF membrane. Thus, employing SNW-1 into PES matrix resulted in a promising nanofiltration membrane for dye separation and moderate salt separation with suitable antifouling properties.     

Preparation of Anti-Fouling Polyethersulfone Ultrafiltration Membrane by an External High Voltage Electric Enhancing Method

In this article, a novel method of applying high voltage (1–5 kV) to the conventional immersion precipitation phase inversion process was used to prepare polyethersulfone ultrafiltration membranes when PVP (30 K) was used as an additive. The effects of the external electric field on the structure, surface functional groups, membrane potential, and surface hydrophilicity of the membranes were researched. Bovine serum albumin (BSA) adsorption amounts on the membranes and the separation performances of the membranes were measured. It was found that the external electric field influenced the surface carbonyl groups, surface hydrophilicity, and potential of the membranes. With the increase of the external voltage, the surface hydrophilicity and the membrane potential decreased. It seemed that the external voltage had no influence on the cross-section structure of the membranes, but the surface porosity density slightly reduced when the external voltage increased. In basic BSA solution, the protein adsorption amount on the electric enhanced membranes was distinctly reduced when compared with an un-enhanced membrane, and the rejection was also improved. Consequently, the prepared electric enhanced PES membranes had distinctive anti-fouling properties.