Membranes, membrane processes, and their applications: Needs, unsolved problems, and challenges of the 1990's

• Published in: Desalination 1990-01, Vol.77 (1-3), p.5-34
• Main Author: Michaels, A S
• Format: Article
• Language: English
• ISSN: 0011-9164
• DOI: 10.1016/0011-9164(90)80002-S

The major limitations of membrane processes were low permeation flux, inadequate permselectivity, inadequate membrane durability, membrane fouling and high equipment or operating costs. These limitations had restricted wider industrial application because the membrane processes were technically impractical, or in most cases, uneconomic. Recent developments in membrane materials and structures to overcome these problems are described. There were new permselective materials, improved thin barrier multilayer laminates and novel permselective structures comprising interpenetrating, immiscible phases. There were innovative membrane process improvements for separations to reduce polarization and fouling. Sorptive and catalytic membrane structures included affinity and ion exchange membranes, immobilized enzyme/catalytic membranes and electrochemical/catalytic membrane processes. Opportunities also existed for integrating membrane processes with other biochemical and physico-chemical processes. Examples included continuous separation by affinity complexation/membrane filtration, dialytic precipitation/membrane filtration, membrane solvent extraction, concentration by cryofiltration and electrochemically-driven transformation/separation systems utilizing permselective membranes.