Composite membranes with a poly (vinylalcohol) (PVA) layer coated on polyacrylonitrile(PAN) support membranes were evaluated for pervaporation separation of water-alcohol mixtures. The PVA /PAN composite membranes as prepared were water permselective for the ethanol concentration range of 60 to 99wt% in the feed

and the separation factors were 800 ￣ 1100

permeate flux was 300 ￣ 450g/m2hat 75℃ (for ethanol concentration in feed 95wt%). The dependence of the permeate flux on temperature was consistent with the Arrhenius relationship

and the separetion factor and permeate flux was increased with increasing operation temoerature. PVA/PAN composite membrane has excellent permselectivity for separating mixutures of iso-propanol(or iso-butyl alcohol

glycerin)and water.