Pervaporation dehydration of aqueous ethanol solution using H-ZSM-5 filled chitosan membranes

H-ZSM-5 filled chitosan (CS) membranes were prepared by incorporating H-ZSM-5 into chitosan for pervaporation dehydration of aqueous ethanol solution. Characterization results revealed that hydroxyl groups on H-ZSM-5 could form hydrogen-bonding interaction with the hydroxyl and amino groups of chitosan, which lowered the crystallinity of membranes and consequently improved the interface morphology. The sorption experiments showed increased degree of swelling (DS) and sorptivity selectivity with increase of H-ZSM-5 content and decrease of Si/Al ratio in H-ZSM-5, respectively. Decreased separation factor of the filled membranes in pervaporation process was mainly attributed to the formation of nanometer-scale voids, and enhancement of hydrogen-bonding interaction by decreasing Si/Al ratio in H-ZSM-5 reduced the amount of nonselective voids accordingly. Compared with chitosan control membrane (permeation flux 54.18 g/m2 h and separation factor 158.02 for 90 wt.% aqueous ethanol solution at 80 °C), the H-ZSM-5(50)-CS-08 membrane (mass ratio of H-ZSM-5(50) to chitosan is 8 wt.%) exhibited the remarkably improved pervaporation performance with permeation flux 230.96 g/m2 h and separation factor 152.82 under the identical experimental condition.