Pervaporation dehydration of water/ethanol/ethyl acetate mixtures using poly(vinyl alcohol)-silica hybrid membranes

The novel organicinorganic 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-2 h-1. (C) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012