Development of aromatic polyamide membranes for pervaporation and vapor permeation

The pervaporation and vapor permeation performances of a series of fluorine -containing aromatic polyamide membranes for various alcohol mixtures were investigated. Compared with pervaporation, vapor permeation effectively inc reases the permselectivity of water. The solubility of alcohol in an aromat ic membrane is higher than that of water, but the diffusivity of water acro ss the membrane is higher than that of the alcohols. In addition, the relat ionship between the polymer structure and pervaporation performance was obt ained. It was found that the permeation rate can be increased by the introd uction of bulky substituted groups and arylene ether groups into the polyme r backbone. (C) 2000 Elsevier Science B.V. All rights reserved.