WATER-ALCOHOL SEPARATION BY PERVAPORATION THROUGH POLY(AMIDE-SULFONAMIDE)S (PASAS) MEMBRANES

Pervaporation membranes derived from seven homopolymers of poly(amide- sulfonamide)s (PASAs) were prepared by casting 10-17% polymer solution s of N,N-dimethylacetamide. The membranes were characterized by sorpti on experiments, scanning electron microscope, and wide-angle X-ray dif fraction. During the pervaporation of 90 wt % aqueous solution of meth anol, ethanol, l-propanol, and 2-propanol, all membranes were preferen tially permeable to water, and their separation factors were mainly de pendent on the molecular weight of the solvent. The exact structure of the PASAs had a profound effect on their pervaporation characteristic s. Polymeric membrane based on N,N'-bis (4-aminophenylsulfonyl)-1,3-di aminopropane and isophthaloyl chloride exhibited the best selectivity factor of 1984 for a 10:90 (by weight) mixture of water/ethanol at 20 degrees C. However, the permeation rates of all materials for dehydrat ion of 90 wt % ethanol were slow in a range of 6.6-34.4 g m(-2) h(-1). (C) 1997 John Wiley & Sons, Inc.