Interpenetrating polymeric network (IPN) membranes of sodium alginate (NaAlg) and various amounts of poly(hydroxyethylmethacrylate) (PHEMA) have been prepared and tested for the pervaporation dehydration of ethanol and tetrahydrofuran (THF). The presence of hydrophilic PHEMA in the IPN matrix was found to be responsible for increase in membrane selectivity to water. NaAlg-PHEMA IPN membrane containing 20 wt % of PHEMA exhibited a selectivity of 571 to water for the water-ethanol mixture and 857 for water-THF mixture. These data are much better than those observed for the pristine NaAlg membrane. However, flux of the IPN membranes was smaller than that of pristine NaAlg membrane. Comparatively higher flux values were observed for water-THF mixture than for water-ethanol mixture. (c) 2006 Wiley Periodicals, Inc.