Dehydration of tetrahydrofuran (THF) by pervaporation using crosslinked copolymer membranes

Tetrahydrofuran (THF) is an important volatile intermediate used in chemical industries and its separation from water is encountered in many application. Three different copolymers of acrylamide with increasing amount of 2-hydroxyethyl methacrylate (HEMA), i.e. PAMHEMA-1, -2 and -3 were synthesized and the crosslinked (gelled) copolymer membranes made from these sol copolymers were used for pervaporative dehydration of THF over the concentration range of 0-14 wt% water in feed. These extremely hydrophilic gel copolymer membranes were found to be highly water selective in both sorption and diffusion through the membranes. Water flux was found to decrease with increase in degree of crosslinking from PAMHEMA-1 to 3 copolymer membranes. Among the three membranes PAMHEMA-1 membrane showed very high water selectivity (216) and reasonable flux (570 gm/m2 h for 0.56 wt% of water in feed at 50 °C temperature). Water was also found to have a strong positive coupling effect on THF permeation. The membranes were found to show both sorption as well as diffusion selectivity for water.