Abstract: It has been recognized generally that glassy polymer membranes preferentially permeate water and elastomer membranes preferentially permeate ethanol.Until now only a few alcohol-selective membranes have been developed such as silicone rubber membrane,having low flux and selectivity toward alcohol.In this paper,preferential separation of ethanol from aqueous solution through hydrophilic PVA/CS blend membrane has been investigated for the t time.The results show that PVA/CS membrane preferentially permeate ethanol at lower ethanol concentration in feed,and the selectivity of chitosan membrane toward alcohol can be greatly improved by introducing water-soluble polymer PVAinto chitosan. The membrane with PVAcontent of 53% (wt%) gives a separation factor 17.1 and a flux of 217 g·m^-2·h^-1at 8.7%(wt%) of ethanol in the feed at 20℃. The separation properties of this membrane were much higher than those of silicone rubber membrane usually used as alcohol-selective one.

Key words: Pervaporation, Poly(vinyl alcohol)/chitosan blend membrane, Watere-thanol mixture