Pervaporation of Methanol–Ethylene Glycol Mixture over Organic–Inorganic Hybrid Membranes

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.