The Study Of Preparation And Antifouling Property Of PVA/PVAm Blend Membrane Based On Polyester Filter Cloth

The membrane bioreactor (MBR) is a new processing technology for a combination of high efficiency membrane separation technology and activated sludge biological treatment unit. MBR in China is mainly used to process domestic sewage, petrochemical, waste water, high concentration organic wastewater, food wastewater, brewery wastewater, ports sewage, printing and dyeing wastewater, etc. Now, MBR is also used in nitrogen and phosphorus removal, drinking water purification and other fields. The scope of the MBR’s application is greatly expanded, but there are problems which restrict it further development. If these problems can be solved which will bring a more competitive, mature market for MBR applications. Energy consumption and membrane fouling are the restrictions on the MBR extensive use. The membrane fouling is a serious impediment to its wide application in practice which directly affects the efficiency and service life of the membrane. The main performances of the membrane fouling are the decline in membrane flux and the increase in membrane cleaning and replacement frequency. Increasing the hydrophilic functional groups of membrane is an effective means to resolve membrane fouling. It mainly includes the choice of hydrophilic materials (PEG, PMMA, CTS) and the choice and conditions of surface modification methods of the polymer film. Such as modification before Membrane preparation, modification after membrane preparation, the plasma surface oxidation, the direct graft polymerization, the ATRP (atom transfer radical polymerization) and doped inorganic particles. The modification of cheap filter cloth material can cause the improving of filtration precision and the performance of anti-pollution of the membrane which have the important meaning to the MBR technology.In this study, containing hydrophilic hydroxyl and/or amine groups, polyvinyl alcohol (PVA) and polyethylene amine (PVAm) were used to increase the hydrophilic and antifouling property of the polyester filter cloth, following wet-coating/drying, cross-linking and soaking procedures. The proportion of PVA to PVAm in coating solution, the thickness of wet-coating and cross-linking time, as well as the content of cross-linking agent in solution were studied to improve the antifouling performance of membranes. The results show that when m(PVA):m(PVAm) was1:1, the thickness of wet-coating on membrane was controlled at100μm, and the content of cross-linking agent was0.2%, with two coating times, the best antifouling composite membrane can be prepared.