Study On Methanol/water Pervaporation Of AA-AN Copolymerization Membrane

Pervaporation, as one of high efficient and economic membrane separation methods, is widely used in ethanol/water solution and achieved to the industry level, but the research and application about pervaporation of methanol/water is rarely. Comparing with ethanol, methanol is more similar with water in molecular weight and polarity. We use Poly vinyl alcohol, acrylic acid and acrylonitrile as the materials, through the aldolisation of PVA and copolymerization of AA and AN, we prepared the composite membrane with balance theory of hydrophilic and hydrophobic water. We used the composite membrane to separate methanol/water solution and test its performance. Related the manufacture of Epichlorohydrin, our purpose is through PV technology separate methanol concentration from 70% to 90%, and then the treated solution can be used in duty-cycle operation.Through copolymerizing AA and AN in different mole ratio, and compare the PV performance with membrane of PVA acetal membrane, we can concluded that, the separation flux of composite membrane is less than PVA acetal membrane, however, when the mole ratio of AA and AN is 1:1, the separation factor is higher than PVA acetal membrane, from the view of PSI, the composite membrane is better, that's the reason of the hydrophilic functional group and hydrophobic functional group ratio proper, it achieved good balance.Through experiments we concluded that the composite membrane made in the condition of 10% PVA, 36%formaldehyde, and 1:1mole ratio of copolymerization of AA and AN, for 75℃temperature heating, the membrane is better than other membranes, and when the thickness of composite membrane is 30μm, the performance of the membrane is best.Testing the membrane made in the optimized condition, we found that the separation range of composite membrane is about 98%-30%, and the tensile strength is 58.3N/mm~2, about heating stability and using stability, the composite membrane is also good.