Functionalized silica–chitosan hybrid membrane for dehydration of ethanol/water azeotrope: Effect of cross-linking on structure and performance

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/l2 h permeation flux and 5282 selectivity for dehydration of ethanol (90 wt%) at 30 °C.