Search

This paper introduces a versatile approach for surface modification of 621-terylene filtration fabric (FF) self-assembled by a dynamic layer-by-layer technique. The hexadecyl trimethyl ammonium bromide (HTAB) and cross-linked polyvinyl alcohol microspheres (PVA-MS) were alternatively deposited on support membrane under a pressure of 0.01 MPa to modify FF. Morphological changes and hydrophilicity of the modified FF were characterized in detail by scanning electron micrograph and water contact angle measurements. Results revealed that PVA-MS could be adsorbed mainly on the surface of FF and water contact angle decreased with the increase of HTAB/PVA-MS bilayer numbers indicating an enhanced hydrophilicity for the modified FF. Backwash experiments of the modified FF exhibited much higher stability of PVA-MS. Protein adsorption experiments were conducted to evaluate the antifouling property of the modified FF. Results indicated that protein adsorption of the membrane surface could be obviously improved by modification, which exhibited superior antifouling property of the modified FF.

This paper introduces a versatile approach for the modification of terylene microporous membrane by PVA-MS layer-by-layer self-assembling to improve its filterability. The preparation conditions including filtration time of the first HTAB layer, reaction time and bilayer number were investigated. The results suggested that suitable filtration time of the first HTAB layer was 8 min and the reaction time was 10 min with suitable HTAB/PVA-MS bilayer numbers. Membrane chemistry, morphological changes and hydrophilicity of the composite membrane were characterized in details by FTIR-ATR spectroscopy, scanning electron micrograph and water dynamic contact angle measurements. Results revealed that PVA-MS could be adsorbed mainly on the surface of the terylene microporous membrane and dynamic contact angle on the terylene microporous membrane surface decreased with the increase of bilayer numbers indicating an enhanced hydrophilicity for the modified terylene microporous membrane. Backwash experiments of composite membranes exhibited much higher stability of the HTAB/PVA-MS active layer. The permeation flux of activated sludge was measured to evaluate the anti-fouling property of composite membranes, and the results showed an enhancement of anti-fouling property of modified composite membranes.

Membranes suffer from operational problems due to fouling in water filtration. Fouling is caused by the build-up of chemicals, bioorganic materials, and biofilms at the membrane surface. The focus of this study was the fabrication and characterization of 4-vinyl pyridine grafted polyvinyl alcohol (PVA-g-4VP) and the modifi cation of nonwoven membrane (NWF) for the prevention of bacterial attachment. The graft copolymerization using Ce(IV) as an initiator was carried out in an aqueous solution. With keeping other conditions constant, the optimum conditions were shown as following: [Ce(IV)]=4 mmol/l, [4VP]=0.15 mol/l, reaction temperature=60°C, reaction time=240 min. NWF membranes were modified by coating of PVA-g-4VP with different graft concentrations, and quaternization of the pyridine groups with benzyl bromide. A significant surface enrichment of vinyl pyridine polymer side chains was observed by Fourier transform infrared-attenuated total refl ectance. The permeability of the membrane was reduced afte...

This article introduced an approach using cross-linked polyvinyl alcohol microspheres (PVA-MS) to form dynamic membrane on the surface of the industry filter cloth instead of the conventional MF/UF membrane to build a membrane bioreactor (MBR) for wastewater treatment. The performance of the dynamic MBR for treating synthetic domestic wastewater and membrane fouling were investigated. For treating synthetic domestic wastewater sequentially, the results of the batch tests showed that the effluent turbidity was less than 4 NTU and SS was zero at the most operation time. The average removal efficiency of CODCr and NH4+-N were 93.18 and 98.6%, respectively. Membrane fouling was mainly caused by sludge layer. The sludge cake and precoated dynamic membrane could be easily removed by brushing. The support membrane permeate flux was almost recovered fully and could be reused again. These results indicated that the precoated dynamic membrane could prevent pollutants and biomass intervening to the surface and inter...