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A facile approach to fabricating the antifouling, high-flux oil/water separation carbon nanotube (CNT) nanohybrid membranes was explored by polymer-mediated surface charging and hydrophilization through vacuum-assisted self-assembly process. The controlled stacking of CNT imparted the membranes hierarchical nanostructure and high water permeation reaching 4592 L m −2 h −1 bar −1 , which was about 10 folds of commercial ultrafiltration membranes used for oil/water separation. Modifying CNT with a series of polymers endowed the membranes with different surface charge and hydrophilicity. The compact hydration layer was formed at the interface of water/membrane by the water trapped in the hierarchical nanostructure to prevent oil from adhering on the membrane surface. Hence, the polymer@CNT nanohybrid membranes possessed underwater superoleophobicity and low oil adhesive force. Moreover, the antifouling properties of as-prepared membranes were evaluated through filtration of oil-in-water emulsions with different surface charges and the results demonstrated that synergetically regulating the surface charge and hydrophilicity could tune the interactions between the foulants and membrane surface, which can efficiently inhibit the irreversible fouling, leading to 100% flux recovery ratio (FRR). The fabrication process of the polymer@CNT nanohybrid membranes with high water permeation, high separation efficiency and excellent antifouling properties may enlighten the great prospects for CNT-based materials in water separation and purification. [ABSTRACT FROM AUTHOR]

A kind of novel electro-neutral nanofiltration (NF) membrane at neutral pH was fabricated by interfacial polymerization from a novel zwitterionic amine monomer PEI-g-SBMA. The zwitterionic amine endowed the resultant NF membrane with an electro-neutral separation layer under neutral condition and enhanced antifouling property via regulation of surface charge balance. The electro-neutral zwitterionic NF membranes (PEI-g-SBMA/TMC) showed a high water flux of 132 L/ (m 2 h MPa), i.e. over 2 times higher than that of the PEI/TMC membranes without grafted SBMA. The PEI-g-SBMA/TMC membrane exhibited a high dye rejection (90.6% for Orange GII) but a low salt rejection (7.1% for NaCl and 50.4% for Na 2 SO 4 ). Meanwhile, the antifouling property against bovine serum albumin (BSA), sodium alginate (SA) and humic acid (HA) was significantly improved compared with the PEI/TMC membranes. The as-fabricated electro-neutral PEI-g-SBMA/TMC membranes with high organics rejection and low salt rejection as well as good antifouling property may find promising application potential in food, pharmaceutical, chemical industry and membrane bioreactor (MBR) processes. [ABSTRACT FROM AUTHOR]

In this study, the copolymers (PS n -co-PEGMA m ) with crosslinked structure were synthesized and blended into polythersulfone (PES) matrix to fabricate membranes via surface segregation method. The incorporation of copolymers affected both the phase separation and surface segregation behaviors during membrane fabrication process. On one hand, the copolymers could affect the formation of nodular structure of the as-prepared membranes for increasing the size of polymeric spheres and generating a loose skin layer, which was testified by atomic force microscope (AFM) surface measurement. As a result, the water permeation flux of membranes increased from 166.9 L m −2 h −1 for the PES control membrane to 333.0 L m −2 h −1 for the PES/PS 3 -co-PEGMA 2 membrane (with 0.80 wt% of copolymer content). On the other hand, the hydrophilic PEO segments in the copolymers could spontaneously migrate to and enrich on the membrane surface, which were demonstrated by X-ray photoelectron spectroscopy (XPS) analysis, as a result, the antifouling properties of the membranes were considerably improved. The separation performance of the membranes was evaluated by bovine serum albumin (BSA) aqueous solution as model system. With incorporation of copolymer as versatile modifier, the permeation flux of BSA aqueous solution increased and the rejection efficiency of all the membranes was 100%. [ABSTRACT FROM AUTHOR]

Hybridization has evolved a powerful toolbox for hierarchical structure manipulation of antifouling membrane surface. In this study, zwitterionic and fluorine-containing moieties are immobilized onto the surface of TiO 2 nanoparticles through the mediation of polydopamine, and the resultant nanoparticles are incorporated into poly(vinylidene fluoride) (PVDF) matrix to simultaneously manipulate the chemical and topological structures of membrane surfaces. The hierarchical topographies of the hybrid membranes arise from the morphology of nanoparticles. The surface heterogeneity of the hybrid membranes arises from the different chemical moieties on nanoparticles, endowing the membrane surfaces with both hydrophilic zwitterionic segments and low surface energy fluorine-containing segments. Due to the favorable hierarchical chemical and physical structures, the hybrid membranes display a remarkable enhancement in oil-fouling-resistant and oil-fouling-release capacities during oil-in-water emulsion filtration: the flux declines at the minimum level of 16.7% and recovers to the maximum level about 100%. It can be anticipated that the present study will offer a physico-chemical coordinated antifouling mechanisms to control membrane oil-fouling for the efficient oil-containing wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract: Based on the molecular structure feature and bioadhesion phenomenon, dopamine was selected to prepare composite membranes. The amine and phenol groups in dopamine, and the catechol groups of polydopamine all could react with acyl chloride groups of trimesoyl chloride (TMC) forming a dense thin film onto porous PES ultrafiltration substrate. The interaction between the thin film and the substrate of the composite membrane was enhanced due to the bioadhesion of polydopamine. The dopamine/TMC composite membranes were characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and water contact angle measurement. The preparation parameters of dopamine/TMC composite membranes including pH value of water phase, reaction time, reaction temperature, and monomer concentrations were investigated, respectively. The separation performance of dopamine/TMC composite membranes was in the nanofiltration range. The composite membranes exhibited long-term structural stability in ethanol and chemical stability in sodium hypochlorite solution. Compared with the others in enhancing the structural stability, the bioadhesion method was simple and time-saving. [Copyright &y& Elsevier]

Abstract: Polyvinyl chloride (PVC) and polyvinyl formal (PVF) blend ultrafiltration membranes were fabricated by non-solvent induced phase separation (NIPS) method with different casting solution composition. The PVC/PVF membranes were characterized and evaluated by scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), water contact angle measurement and performance measurement. The results showed that PVF played the role of pore formation agent during the NIPS process, and both of porosity and the mean pore size of the membranes were increased with the increased dosage of PVF. Simultaneously, PVF was enriched to membrane surface via spontaneous surface segregation and the membrane surface hydrophilicity was greatly elevated, which implied the remarkably enhanced antifouling property. The robust residence of PVF on the membrane surface was confirmed by a long-term test of incubating membranes in deionized water, which revealed the stable antifouling property of PVC/PVF membranes. Therefore, PVF could be explored as a potential versatile modifier for fabricating high performance ultrafiltration membranes. [Copyright &y& Elsevier]

Abstract: In the present study, an in situ approach to pH and temperature responsive membranes is developed. The membrane matrix is formed through bulk polymerization and crosslinking of liquid monomer 2-hydroxyethyl methacrylate (HEMA) while the membrane pores are formed by the templating of inorganic particles. The functional monomers methacrylic acid (MAA) and N-isopropylacrylamide (NIPAAm) are incorporated into membrane casting solution in order to confer membranes with pH and temperature responsive properties. The poly(HEMA/MAA) membranes exhibit a reversible pH-dependent water flux, while the poly(HEMA/NIPAAm) membranes exhibit a reversible temperature-dependent water flux. The flux of the poly(HEMA/MAA) membrane increased by 70% when pH was decreased from 10.0 to 2.0, while the flux poly(HEMA/NIPAAm) membrane increased by 150% when temperature was increased from 20 to 45 °C. The protein adsorption and antifouling performance of the poly(HEMA/MAA) and poly(HEMA/NIPAAm) membranes also exhibit pH and temperature responsive properties. [Copyright &y& Elsevier]

Abstract: Antifouling membrane surfaces capable of reducing biofouling are highly desirable in a broad range of applications. In this study, amphiphilic membrane surfaces, derived from block copolymers bearing hydrophilic poly(ethylene oxide) (PEO) and low surface energy polydimethylsiloxane (PDMS) segments, have been constructed via surface segregation during the standard phase inversion process. The surface chemical features of the membranes are confirmed by contact angle measurement, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and surface energy analysis. The PEO segments are utilized to prevent biofoulant adsorption (fouling-resistance) whereas the PDMS segments are utilized to drive away the adsorbed biofoulants (fouling-release). The resultant surfaces exhibit better antifouling properties compared with the control polyethersulfone (PES) membrane when using bovine serum albumin (BSA), sodium alginate (SA) and yeast as three model biofoulants (proteins, polysaccharides and microorganisms). During the filtration of model biofoulant aqueous solutions, both irreversible and reversible flux declines are remarkably decreased and the flux recovery is retained completely after simple hydraulic washing. Static and dynamic biofoulants adsorption experiments reveal the synergistic effect of the PEO and PDMS segments on biofouling-resistance and biofouling-release. It is also found that the biofouling can be significantly reduced by the coexistence of optimized hydrophilic microdomains, low surface energy microdomains, and shear flow near membrane surfaces. Hopefully, the demonstrated attempt of membrane surface construction is favorable to prepare a wide spectrum of environmentally benign antifouling membranes. [Copyright &y& Elsevier]

In this study, a solvent-free approachto antifouling membranes is tentatively presented. The membrane bulkmatrix is formed through bulk polymerization of liquid monomer 2-hydroxyethylmethacrylate (HEMA) in the absence of an organic solvent. The membranepores are formed via removal of silica particles generated from thesol–gel process of tetraethyl orthosilicate. The membraneshave a homogeneous structure and acquire water flux around 1020 Lm–2h–1at 0.1 MPa. The ratesof rejection of the yeast and oil droplet for all the polyHEMA membranesare above 97.0 and 99.0%, respectively. The polyHEMA membranes exhibitstrong hydrophilic and excellent fouling resistance properties asa result of hydrophilic HEMA. The flux recovery ratio is as high as91.0% using protein as a foulant. After the fluorine-containing additivedodecafluoroheptyl methacrylate (DFHM) had been blended in a castingsolution, the poly(HEMA/DFHM) membranes possess an amphiphilic surfaceand exhibit excellent fouling resistance as well as fouling releaseproperties. The flux recovery ratio is >90%, and the total fluxdecline ratio is as low as 11.7% using an oil/water emulsion as thefoulant. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a novel kind of fluorinated polyacrylonitrile (PAN) membrane is prepared by grafting perfluoroalkyl groups onto aminated PAN membrane surface through the acylation reaction. The surface composition of the fluorinated PAN membranes is confirmed by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The changes of membrane surface hydrophilicity, chemical heterogeneity and surface free energy after fluorination treatment are evaluated by contact angle measurement. When utilized for the ultrafiltration separation of oil/water emulsion, protein aqueous solution and polysaccharide aqueous solution, the fluorinated PAN membranes exhibit superior fouling release properties, that is, high flux recovery ratio (∼99%) and low total flux decline ratio (the minimal value is ∼13%). These results demonstrate the feasibility of grafting perfluoroalkyl groups onto the membrane surfaces to manipulate the physicochemical features and improve antifouling property. Moreover, the fluorinated PAN membranes acquire distinct reversible multi-responsive properties under ionic strength and pH stimuli. [Copyright &y& Elsevier]

Polyvinyl chloride (PVC) and chlorinated polyvinyl chloride(CPVC)were used as membrane materials to fabricate blend ultrafiltrationmembranes. Polyethylene glycol (PEG2000) and polyethylene oxide-polypropyleneoxide-polyethylene oxide triblock copolymer (Pluronic F127) were usedas both pore forming agent and surface modifier to improve the permeability.The advantage of amphiphilic Pluronic F127 is that it enables higher−CH2–CH2–O– segmentcoverage on the membrane surfaces. The increase of CPVC proportionin membrane materials could improve the water fluxes of PVC/CPVC blendmembranes with the slight change of protein rejection ratios. Allthe PVC/CPVC blend membranes with an additive of Pluronic F127 haveexcellent antifouling property. The blend method is an appropriateway to prepare new antifouling PVC/CPVC ultrafiltration membraneswhich have lower cost and better performance. [ABSTRACT FROM AUTHOR]

Abstract: A novel approach was developed in the present work that antifouling composite nanofiltration membranes were directly and efficiently fabricated with antifouling ultrafiltration membranes. Pluronic F127/polyethersulfone (PES) ultrafiltration membranes with enriched poly(ethylene oxide) (PEO) segments on the surfaces were selected as supporting layers and piperaine (PIP) and trimesoyl chloride (TMC) were used as monomers to fabricate the composite polyamide nanofiltration membranes. X-ray photoelectron spectroscopy (XPS) measurement showed that there were higher O contents on the surfaces of nanofiltration membranes, the high solution O1s core-level XPS spectra gave important information that the appearance of PEO segments in the polyamide layer. The water permeability and rejection property of the composite nanofiltration membrane with Pluronic F127 in substrate were better than that without Pluronic F127. Three different pollution systems were chosen to prove the excellent antifouling property of the composite nanofiltration membranes, whose water fluxes were completely recovered by simple water washing. [Copyright &y& Elsevier]

Abstract: A novel kind of block-like copolymer poly(butyl methacrylate)-b-poly(methacrylic acid)-b-poly(hexafluorobutyl methacrylate) (PBMA-b-PMAA-b-PHFBM) with hydrophobic segments, hydrophilic segments and fluorine-containing segments was prepared by free radical polymerization method. The copolymers were incorporated into PES ultrafiltration membranes through a wet phase inversion method. The surface enrichment of hydrophilic segments and fluorine-containing segments of the copolymer due to the spontaneous and forced surface segregation during non-solvent induced phase separation process was confirmed by X-ray photoelectron spectroscopy (XPS). The modified membranes displayed distinct pH-responsive permeability. The water flux of PES/PBMA5-b-PMAA4.6-b-PHFBM1.1 membrane could significantly decrease from 150L/(m2 h) to 75L/(m2 h) in the pH region of 4.8–6.2. Meanwhile, the modified membranes exhibited desirable fouling release property mainly derived from fluorine-containing segments. The highest cleaning efficiency of the modified membranes could reach 57.4% compared with that less than 5% of the blank membranes. [Copyright &y& Elsevier]

Abstract: The suppression of nonspecific protein adsorption to synthetic surfaces, especially membrane surfaces, represents a severe challenge in biotechnological, biomedical and biosensor community. In this work, we utilize short-chain molecules rather than long-chain polymers as modifiers for antibiofouling membrane surface construction. Three types of natural amino acids, including lysine, glycine, and serine, were chemically grafted onto membranes via carbodiimide chemistry to render highly hydrophilic surfaces, which displayed the intrinsic advantages in high surface coverage, three-dimensional modification, and unsacrificed permeability. Although hydrophilicity of membranes modified with these three types of amino acids was quite close, only lysine modified membrane surface showed superior protein fouling resistance under both static exposure and dynamic filtration conditions. Molecular dynamics simulation study was performed to tentatively interpret the underlying differences. [ABSTRACT FROM AUTHOR]

Abstract: In order to improve the performance of poly(vinylidene fluoride) (PVDF) microporous membranes, cellulose acetate (CA) was used as a hydrophilic additive to blend with PVDF for membrane preparation by phase inversion in a wet process. Scanning electron microscopy (SEM) revealed that the fabricated PVDF membranes have the typical asymmetric structure. The water contact angles of the PVDF membranes were decreased, the water contents of the membranes were increased, and the amounts of adsorbed protein were dramatically decreased due to the addition of CA. X-ray photoelectron spectroscopy (XPS) analysis confirmed the enrichment of CA segments on the PVDF membrane surfaces due to surface segregation for lowering of interface free energy. The shift of F 1s binding energy from 687.8 to 687.0eV indicated that there are interactions between PVDF and the added CA. All prepared PVDF microfiltration membranes have higher flux recovery ratio and lower membrane fouling in protein separation and purification. [Copyright &y& Elsevier]

Abstract: Due to its rigid and tunable structure, inorganic pore-forming agent may exhibit the great potential in fabricating membranes with high flux. In this study, in situ generation of silica (SiO2) nanoparticles was coupled with polymer phase separation process for preparing cellulose acetate (CA) membranes with enhanced permeation property. The pH values of coagulation bath were adjusted with acid and basic solutions to perform the hydrolysis and polycondensation reaction of tetraethyl orthosilicate (TEOS) precursor at moderate rate. The pore-forming mechanism of the generated SiO2 nanoparticles was tentatively proposed. Majority of SiO2 nanoparticles were instantly extracted into the coagulation bath during the phase inversion process and the spaces they once occupied turned into the pores of membranes, ensuring the great improved permeability of the CA membranes. The remained nanoparticles were mostly enriched and homogenously distributed on the membrane surface without lowering the hydrophilicity of CA membranes. Ultrafiltration experiments showed that the as-fabricated CA membranes exhibited higher permeability and kept superior antifouling properties compared with the control CA membrane in oil/water emulsion separation. [Copyright &y& Elsevier]

Abstract: Facile graft polymerization of methacrylic acid (MAA) onto polyethersulfone (PES) using benzoyl peroxide (BPO) as chemical initiator had been developed. The polymerization was carried out in a heterogeneous polymer–monomer reaction system using water as reaction medium. The crucial parameters affecting the graft yield, such as monomer concentration, reaction time and temperature, were studied. The amount of grafted PMAA on PES was increased with increasing monomer concentration and reaction time. The optimum temperature for the grafting was around 75°C. The graft polymers produced herein were cast into ultrafiltration membranes via phase inversion process. The cross-sectional morphology and surface composition of the membranes were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. Remarkable surface enrichment of the hydrophilic MAA segment in the membrane was revealed by XPS analysis. Due to the pH-induced conformational transition of the PMAA chains, the permeability of the membranes cast from the grafted polymers displayed pronounced pH dependence, which was large under low pH values and small under high pH values. [Copyright &y& Elsevier]

To improve the surface coverage of polyvinylpyrrolidone (PVP) on membrane surfaces and further enhance the antifouling property, a silica−PVP nanocomposite was synthesized and used as a novel hydrophilic additive to modify polyethersulfone (PES) membranes. Transmission electron microscopy (TEM) observation showed that PES membranes, using additives of PVP and silica−PVP nanocomposites, have similar asymmetric structures. X-ray photoelectron spectroscopy (XPS) measurement indicated that the near-surface coverage of PVP for PES membrane with a silica−PVP nanocomposite additive is greater than that with a PVP additive. Protein ultrafiltration experiment also showed that the antifouling ability of PES membrane with a silica-PVP nanocomposite additive is stronger than that with a PVP additive. The hydrophilic modification with a silica−PVP nanocomposite is an appropriate method for improved antifouling property of PES ultrafiltration membranes. [ABSTRACT FROM AUTHOR]

Abstract: Adsorption and recovery of methylene blue (MB) from aqueous solution through ultrafiltration technique with polyethersulfone (PES) membrane was developed. Cationic dye MB can be adsorbed by PES membrane from aqueous solution. The amount of adsorbed MB on PES membrane was higher at the condition of basic solution and lower ionic strength. The electrostatic interaction may be the important driving force of MB adsorption. During ultrafiltration, the rejection ratio of MB can reach 100% in the initial operation stage due to convection mass transport through membrane pores and adsorption of MB on the surface and pores of PES membrane. The final recovery of MB in the permeate solution was easily achieved by decreasing the solution pH to desorb MB. The adsorption and recovery of dyes from aqueous solution through ultrafiltration technique have potential application in wastewater treatment. [Copyright &y& Elsevier]

Abstract: Modified cellulose acetate (CA) ultrafiltration membranes were prepared using Pluronic F127 block copolymer as both pore-forming agent and surface modification agent. The water content of modified CA membranes increased with an increase of Pluronic F127 content in the casting solutions. The scanning electron microscopy (SEM) photographs showed that the modified CA membranes had thinner top layer and bigger pore volume in the porous sub-layer compared to the CA control membrane. The decrease of static water contact angle with an increase in Pluronic F127 content indicated an increase of surface hydrophilicity. The results of Fourier transform infrared spectrometer (FT-IR) analysis confirmed that most of Pluronic F127 has been leached out from the modified CA membranes. The ultrafiltration experiments revealed that the addition of Pluronic F127 influenced the permeation performance of the membranes, all the modified CA membranes exhibited higher water flux and higher bovine serum albumin (BSA) rejection ratios than those of the CA control membrane. [Copyright &y& Elsevier]

For porous membranes, membrane porosity determines permeability whereas membrane pore size determines selectivity. In many cases, increasing membrane porosity can elevate the permeability but often sacrifices the selectivity due to the accompanying increase of pore sizes. In this study, an in-situ assembly process is incorporated into the membrane formation process to manipulate membrane surface porosity and pore sizes. Amphiphilic copolymer, Pluronic F127, is utilized as a pore-forming agent in the casting solution, and tannin (TA) is utilized as an additive in the coagulation bath. During the membrane formation process, the in-situ assembly of Pluronic F127 and TA via hydrogen bonding interaction can disturb the nucleation and growth process of the membrane formation, increasing membrane surface pore density and decreasing membrane surface pore sizes simultaneously. With the increase of TA content from 0 wt% to 6 wt%, the membrane pore density is increased from 18 to 61 every square micron, and the surface pore sizes are decreased from 17.4 ± 1.4 to 9.3 ± 0.4 nm. The surface porosity, as a comprehensive result of the surface pore density and sizes, is increased from 1.87 ± 0.02% to 2.89 ± 0.17%, then decreased to 1.67 ± 0.19%. The membrane with the TA content of 2 wt% exhibits high separation performance with the initial flux of 412 ± 29 Lm −2 h −1 bar −1 , and the distinguished rejections for bovine serum albumin and dextran (150 kDa) of 99.0 ± 0.1% and 90.9 ± 0.6%. [ABSTRACT FROM AUTHOR]

In this study, a green approach to prepare both porous and dense antifouling membranes was developed through solvent-free bulk polymerization of the casting solution containing 2-hydroxyethyl methacrylate (HEMA) and pre-dispersed silica nanoparticles in two glass sheets under pressure. Porous polyHEMA membranes were prepared via removing the silica nanoparticles embedded in the polymer matrix. Dense poly(HEMA/MAA)/SiO 2 membranes were fabricated by adding methacrylic acid (MAA) as co-monomer without removing the silica nanoparticles. Membrane thickness could be conveniently controlled by varying the distance between the two slide glasses. Field emission scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle measurement were employed to characterize the morphology and surface chemical composition of the resultant membranes. The porous polyHEMA membranes exhibited high efficiency in purification of bovine serum albumin (BSA) from BSA/yeast solution while the dense poly(HEMA/MAA)/SiO 2 membranes exhibited high rejection of orange GII. Both porous membranes and dense membranes exhibited strong hydrophilicity as a result of hydrophilic monomer HEMA, leading to good antifouling properties. [ABSTRACT FROM AUTHOR]

Abstracts: The composite nanofiltration membranes were prepared via interfacial polymerization of tetraethylenepentamine (TEPA) and 1,3,5-benzenetricarbonyl trichloride (TMC). The improved performance of the composite nanofiltratiom membranes by adding calcium chloride in aqueous phase during the interfacial polymerization was verified in terms of pure water permeability, rejection of different solutes including dyes and inorganic salts and chlorine resistance. The results showed that the pure water permeability of composite nanofiltration membranes would acquire a remarkable increase with a slight decrease in solute rejections under the optimized addition of CaCl2. The addition of CaCl2 also dramatically enhanced the chloride resistance of composite nanofiltration membranes in comparison with the control membranes prepared without CaCl2 added. Therefore, inorganic salts like CaCl2 could be considered as a potential additive to enhance the performance of composite nanofiltration membranes. [Copyright &y& Elsevier]

Abstract: The severe swelling behavior of most hydrophobic membranes has always been an obstinate problem when separating organic mixtures by pervaporation. In some cases, hydrophilic membranes may be an appropriate alternative. In this study, amphiphilic copolymer Pluronic F127 was employed as a surface modifier to fabricate polyethersulfone (PES) asymmetric pervaporation membranes via surface segregation. The scanning electron microscopy (SEM) photographs showed an asymmetric structure of PES/Pluronic F127 membranes. The Fourier transform-infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and static water contact angle measurements confirmed the hydrophilic modification of the membrane surface. Based on the distinct difference of solubility in water between thiophene and n-octane, the prepared membranes were utilized to remove thiophene from n-octane by pervaporation. The effect of Pluronic F127 content on the pervaporation performance was evaluated experimentally. It has been found that both the permeation flux and enrichment factor exhibited a peak value of approximately 60wt% of the Pluronic F127 content. The highest enrichment factor was around 3.50 with a permeation flux of 3.10kg/(m2 h) for 500mg/L sulfur in the feed at 30°C. The influence of various operating parameters on the pervaporation performance was extensively investigated. [Copyright &y& Elsevier]

Thin film nanocomposite (TFN) membranes incorporated with graphene quantum dots (GQDs) were fabricated with enhanced water permeability and antifouling property. Owing to the small size, stable dispersion and active functional groups, GQDs were embedded into polyamide (PA) layer during the interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC) in a facile way. The surface chemical features and morphologies of the resultant TFN membranes were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), water contact angle, zeta potential, scanning electron microscope (SEM) and atomic force microscopy (AFM) measurements. The surface roughness of the TFN membranes decreased and the surface hydrophilicity of the TFN membranes enhanced with the increase of the GQDs content. According to nanofiltration (NF) experiments, the highest water flux of the TFN membranes reached up to 102.0 L/(m 2 h) under operation pressure of 0.2 MPa, which was nearly 6.8 times as much as that of the pristine PA membrane. The TFN membranes also exhibited excellent antifouling performance that the steady water flux of the as-fabricated membrane under harsh fouling condition was about 4 times as much as that of the pristine PA membrane. This study may present a useful attempt of using carbon materials in fabricating high flux and antifouling membranes. [ABSTRACT FROM AUTHOR]

Membrane technology has been broadly utilized in water purification including wastewater treatment, seawater or brackish water desalination. However, it often suffers from the severe membrane fouling due to the nonspecific interactions between membrane surface and foulants. Antifouling membrane surface construction thus becomes an everlasting and ubiquitous issue, where chemistry plays a critical role in membrane material design, hierarchical structure manipulation, antifouling mechanism integration and separation performance intensification. Many emerging chemistries enable the rational design and construction of state-of-the-art antifouling membrane surfaces. This review will highlight the recent progress in antifouling membrane surface construction with a focus on five promising classes of chemistries: bioinspired adhesion chemistry, supramolecular chemistry, mineralization chemistry, click chemistry and coupling chemistry. The contribution of chemistries to the physico-chemical structure, antifouling properties, separation performance and long-term durability of membranes will be elaborated. Major challenges and perspectives on future directions of chemistries in antifouling membrane surface construction will also be tentatively delineated. [ABSTRACT FROM AUTHOR]