Using genipin as a "green" crosslinker to fabricate chitosan membranes for pervaporative dehydration of isopropanol

Chitosan membranes were fabricated using naturally-occurring ecofriendly genipin (GP) as a "green" alternative crosslinking agent to replace conventionally used glutaraldehyde (GA). Both GP- and GA-crosslinked chitosan membranes were tested for pervaporative dehydration of isopropanol and characterized by surface energy analyses. The GP-crosslinked chitosan membranes were demonstrated to compare favorably to GA-crosslinked membranes in terms of membrane permselectivity. At a given content of crosslinking agent in the membrane, GP-crosslinked chitosan membranes showed a higher hydrophilicity than chitosan membranes crosslinked with GA. The effects of crosslinker content and operating conditions (including feed concentration and temperature) on the pervaporation performance for isopropanol dehydration were also investigated. It was revealed that the observed increase in permeation flux with an increase in temperature was primarily due to increased driving force for the permeation, and the membrane permeability to both permeants was actually lowered, to a lesser extent, with an increase in temperature.