APPLICATION OF PERVAPORATION AND VAPOR PERMEATION PROCESSES TO SEPARATE AQUEOUS-ETHANOL SOLUTION THROUGH CHEMICALLY-MODIFIED NYLON-4 MEMBRANES

The pervaporation performance of a nylon 4 membrane, chemically grafte d by N,N-dimethylaminoethyl methacrylate (DMAEM), DMAEM-g-N4, was stud ied by measurement of the permeation ratio and the pervaporation separ ation index. It was found that the water permselectivity and permeatio n rate for the chemically modified Nylon 4 membrane were higher than t hose of the unmodified Nylon 4 membrane. Optimum pervaporation results , a separation factor of 28.3, and a permeation rate of 439 g/m(2).h, were obtained when the degree of grafting was 12.7%. It was also found that all the permeation ratios at low temperature were less than unit y. In addition, compared with pervaporation, vapor permeation effectiv ely increases the permselectivity of water.