Application of Pervaporation and Vapor Permeation Processes to Separate Aqueous Ethanoi Solution through Chemically Modified Nylon 4 Membranes

The pervaporation performance of a nylon 4 membrane, chemically grafted by N,N-dimethylaminoethyl methacrylate (DMAEM), DMAEM-g-N4, was studied by measurement of the permeation ratio and the pervaporation separation index. It was found that the water permselectivity and permeationrate for the chemically modified Nylon 4 membrane were higher than those of the unmodified Nylon 4 membrane. Optimum pervaporation results, a separation factor of 28·3, and a permeation rate of 439 g/m2-h, were obtained when the degTee of grafting was 12·7%. It was also found that all the permeation ratios at low temperature were less than unity. In addition, compared with pervaporation, vapor permeation effectively increases the permselectivity of water.