Alginate membranes for the pervaporation dehydration of ethanol-water and isopropanol-water mixtures were prepared and tested. The sodium alginate membrane was water soluble and mechanically weak but it showed promising performance for the pervaporation dehydration. To control the water solubility the sodium alginate membrane was crosslinked ionically using various divalent and trivalent ions. Among them the alginate membrane crosslinked with Ca2+ ion showed the highest pervaporation performance in terms of the flux and separation factors.