Crosslinked organic-inorganic hybrid chitosan membranes were obtained from blending chitosan and gamma-(glycidyloxypropyl)trimethoxy-silane (GPTMS) in acetic acid aqueous Solution. The hydrophilicity of the modified membranes was not significantly decreased, so as to result in good permselectivity and high permeation flux in pervaporative dehydration on a 70 wt.% isopropanol-water (IPA-H2O) solution. A flux of 1730 g/(m(2) h) and a separation factor of 694 were found with the chitosan membrane containing 5 wt.% GPTMS. Both of the crosslinked and organic-inorganic hybrid structures contribute to stabilize the membranes to maintain the performance of the membranes in a 140 days long-term operation. (c) 2004 Elsevier B.V. All rights reserved.