SEPARATION OF LIQUID-MIXTURES BY USING POLYMER MEMBRANES .4. WATER-ALCOHOL SEPARATION BY PERVAPORATION THROUGH MODIFIED ACRYLONITRILE GRAFTED POLYVINYL-ALCOHOL COPOLYMER (PVA-G-AN) MEMBRANES

The acrylonitrile (AN) grafted onto polyvinyl alcohol (PVA) can improve the mechanical properties and water resistance of PVA; however, its hydrophilicity is decreased. Prepared PVA-g-AN membranes through modification with the NaOH and HCHO aqueous solutions can enhance its hydrophilicity. This modified PVA-g-AN membranes were used to separate alcohol/water solution with the pervaporation method. The flux was increased from 0.72 kg/m2 h of the original membrane to 2.06 kg/m2 h of the modified membrane. Moreover, adding a small quantity of CoSO4 to the water-alcohol mixture can simultaneously increase the separation factor.