In-situ crosslinked PVA/organosilica hybrid membranes for pervaporation separations

• PVA membrane with PTES and DEDPS as novel crosslinker and organosilica precursor.
• Organosilane type affects the membrane morphology and pervaporation performance.
• PVA membrane loaded with 4 mmol/g PTES has both improved flux and separation factor.
• A mild thermal treatment enhances the separation performance efficiently.

In this work, two novel poly(vinyl alcohol) (PVA)/organosilica hybrid membranes are developed via the sol–gel process, with phenyltriethoxysilane (PTES) and diethoxydiphenylsilane (DEDPS) as crosslinkers and organosilica precursors, and employed for ethanol dehydration via pervaporation. Effects of organosilane type on the membrane morphology, physicochemical properties and pervaporation performance of the as-fabricated membranes are studied. In addition, the effects of the organosilane loading and the thermal treatment temperature on the physicochemical properties and pervaporation performance of the membrane are explored systematically. Various characterization techniques (FT-IR, TGA, SEM, etc) are employed to illuminate physicochemical changes of membranes. The optimal pervaporation performance of PVA–PTES hybrid membrane with 0.4 mmol/g PTES loading and thermally treated at 80 °C has a flux of 145 g/m2 h and a separation factor of 1026 for the pervaporation dehydration of 85% ethanol aqueous solution at 40 °C.

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