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New organic–inorganic hybrid membranes prepared from chitosan, polyvinylpyrrolidone (PVP), and 1,2-bis(triethoxysilyl)ethane (BTEE) were used for pervaporation separation of methanol–ethylene glycol (EG) mixtures. A semi-interpenetrating network structure at the molecular scale was formed via condensation between chitosan and BTEE in the hybrid membranes. The self-condensation reaction of BTEE took place to form silica nanoparticles. The as-prepared hybrid membranes have denser packing of polymer chains, and higher mechanical strength than their untreated blended counterparts. BTEE hybridization efficiently decreased the membrane swelling in methanol–EG mixture, and enhanced methanol sorption selectivity. Effect of BTEE loading, feed temperature, and feed content on pervaporation performance was investigated in detail. Methanol/EG selectivity increased significantly, whereas membrane permeance decreased, with increasing BTEE loading. The membrane containing 10.4 wt % BTEE has the highest separation factor of 6129 for separation of methanol (6 wt %)–EG mixture at 60 °C.

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. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

The novel organic-inorganic hybrid membranes were prepared from poly(vinyl alcohol) (PVA) and vinyltriethoxysilane (VTES). They were characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and contact angle metering. The as-prepared membranes are formed at a molecular scale at a low VTES content. Aggregations in the surface of the as-prepared membranes were clearly evident above 18.43 wt % VTES loading. The introduction of VTES into the PVA matrix resulted in a decrease in the crystalline and an increase in compactness and thermal stability of the as-prepared membranes. Silica hybridization reduced the swelling of the as-prepared membranes in water/ethanol/ethyl acetate mixtures, decreased the permeation flux, and remarkably enhanced water permselectivity in pervaporation dehydration of ethanol/ethyl acetate aqueous solution. The hybrid membrane with 24.04 wt % VTES has the highest separation factor of 1079 and permeation flux of 540 g m À2 h À1 .