Separation of Aqueous Isopropanol Through Chitosan/Poly (Vinyl Alcohol) Blended Membranes by Pervaporation

Blend membranes consisting of chitosan/poly (vinyl alcohol) (CS/PVA) were prepared from a solution casting method and characterized via the pervaporation separation of isopropanol-water mixtures. The solution of pure chitosan was blended with poly(vinyl alcohol) at different compositions. The miscibility of the blended polymers was determined. Criteria for miscibility was based on the clarity of the blend and the transparency of the membrane obtained. The effects of feed concentration and chitosan content in membrane on the permeation flux and separation factor were also investigated. For the dehydration of 90 wt.% of isopropanol-water mixtures the performance of the blend ratio of 30:70 (CS:PVA) exhibited the highest separation factor. It was shown that under the same operating conditions, the pervaporation separation index (PSI) for homogeneous membranes were higher than that of blended membranes for the entire feed concentrations.Key Words: Blend, Chitosan, Poly (vinyl alcohol), Miscibility, Pervaporation.