Sodium 2-formylbenzenesulfonatepolysiloxane (SBAPTS) was synthesized, while chitosan was modified to N-o-sulphonic acid benzyl chitosan (NSBC). NSBC SBAPTS hybrid membranes were prepared for pervaporation (PV) dehydration of water ethanol mixture. Grafting of -SO3H groups was achieved on both segments (organic and inorganic) of hybrid membranes. Membrane composition and cross-linking density were systematically optimized to explore the effect of membrane structure on its PV performance. Most suitable hybrid membrane (CPS-a) showed 0.59 kg/l(2) h permeation flux and 5282 selectivity for dehydration of ethanol (90 wt%) at 30 degrees C. (C) 2013 Elsevier B.V. All rights reserved.