The development of pervaporation membranes for alcohol dehydration

Abstract

This research work aims to investigate important factors governing the separation process in pervaporation membranes, and to develop polyimide pervaporation membranes for the separation of aqueous alcohol mixtures. Firstly, the effects of operating conditions on separation performance for the dehydration of alcohol mixtures through commercial polyvinyl alcohol membranes were elaborated. In addition, asymmetric P84 co-polyimide membranes for pervaporation dehydration of isopropanol (IPA) were developed by a dry-wet phase inversion method and the influence of non-solvent addition in dope solution and post heat-treatment on membrane formation and separation properties was examined. An in-depth study of sorption, swelling, and permeation of aqueous ethanol, IPA, and tert-butanol through P84 co-polyimide membranes had been conducted as well. Further study was extended to cross-linking modification of P84 co-polyimide membranes with diamine compounds. Finally, zeolite molecular sieves 5A and 13X particles were embedded into P84 dense films and both permeability and selectivity were significantly enhanced.