Influence of double-network interpenetration on ethanol dehydration performance of PVA-based pervaporation membranes

Thermal crosslinked double-network poly (vinyl alcohol) (PVA) is prepared by applying the sequential method. The obtained membrane is characterized by thermogravimetric analysis (TGA), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy and contact angle analyses. It is concluded from FTIR analysis, contact angle measurements and measuring of swelling degree at different feed concentrations that the interpenetrating of the second network, that is the double network (DN), decreases the hydrophilicity of the membrane, while improving the thermal behavior and stability under high temperature. For the sake of the comparison of PVA and DN-PVAs selectivity, total permeation flux, individual fluxes and pervaporation separation index are evaluated for the dehydration of ethanol solution with a feed composition of 85/15 wt% ethanol/water solution at 40–60 °C. Furthermore, the effect of feed temperature on the permeation flux is expressed by the Arrhenius relationship. The performance of DN-PVAs membrane is appraised according to the change in feed concentration and operating temperature. The ethanol concentration in the feed is 75–95 wt% the DN-PVAs has flux values in the range of 41–414 g/m 2 h and separation factor of 105–376 at the operating temperature 40–60 °C.