Chitosan/polyvinylpyrrolidone-silica hybrid membranes for pervaporation separation of methanol/ethylene glycol azeotrope

Chitosan (CS)/polyvinylpyrrolidone (PVP)-silica hybrid membranes are prepared to separate the methanol/ethylene glycol (EG) azeotrope. These hybrid membranes are formed in semi-interpenetrating network structure at the molecular scale via sol-gel reactions between CS and tetraethoxysilane (TEOS). The physico-chemical property and morphology of the as-prepared membranes are investigated in detail. They have lower crystallinity, higher thermal stability, and denser structure than the pristine CS membrane and its blending counterpart. The as-prepared hybrid membranes demonstrate excellent performances and a great potential in pervaporation separation of methanol/EG. Silica-hybridization depressed the swelling degree of membranes in the azeotrope, and remarkably enhanced methanol sorption selectivity. The membrane containing 7.77 wt % PVP and 14.52 wt % TEOS has a permeation flux of 0.119 kg m-2 h-1 and separation factor of 1899. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013