Preparation and dehumidification performance of composite membrane with PVA/gelatin–silica hybrid skin layer

A facile and efficient approach inspired by biomimetic mineralization process was devised to prepare PVA/gelatin–silica hybrid defect-free skin layer through gelatin-induced in situ synthesis of silica particles within PVA bulk. Effect of silica particles incorporation on the physicochemical structures in terms of glass transition temperature (Tg), crystallinity and free volume properties, was systematically investigated. Sorption experiment revealed the identical changing trend between diffusion coefficient and separation performance, indicating that diffusion was the rate-limiting step of the process. Effects of silicate concentration and pH value of the casting solution on membrane separation performance were investigated using propylene/water vapor as a model system. When silicate concentration was 30 mM at pH 5.0 or 7.0, the membrane exhibited the optimum permeance and separation factor simultaneously. Effects of operating parameters, such as operating temperature, feed pressure and feed flowrate on the dehumidification performance were also inspected.

Research highlights▶ Composite membrane with PVA/gelatin-silica hybrid skin layer was fabricated. ▶ Gelatin induced the formation of silica particles within the membrane matrix. ▶ The membranes inherited excellent film-forming property. ▶ The membranes displayed desirable separation performance for gas dehydration.