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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 modification 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/1, [4VP]=0.15 tool/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 reflectance. The permeability of the membrane was reduced after modification. The antimicrobial activity of the modified membrane was measured by 2,3,5-Triphenyl tetrazolium chloride-dehydrogenase. The PVA-g-4VP modified NWF membrane exhibited a higher antimicrobial activity at a higher graft concentration than PVA modified NWF membrane. [ABSTRACT FROM AUTHOR]

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 interior of the support membrane which was helpful to alleviate support membrane fouling. The experimental results demonstrated that the novel dynamic membrane showed highly anti-fouling characteristics in the MBR and could be a potential technology for wastewater treatment. [ABSTRACT FROM AUTHOR]