Section 18 - Membranes for electrochemical cells

Abstract

This chapter discusses the role of membranes in electrochemical cells. Elecrololysis is a widely used method in industry for the manufacture of a range of chemicals, both inorganic and organic. Many of these processes rely on the use of membranes in the cells to achieve high selectivity and efficiency. The notable use of membranes in electrolysis is in chlor-alkali for the production of chlorine and caustic soda, perfluoropolymer cation exchange membranes were specially researched and developed for this application. The chapter provides a list of some applications of membranes in electrosynthesis and also in effluent treatment, and recycling. It reveals that in electrochemical processes it is necessary to separate the processes occurring at the anode and cathode with membranes for reasons of high yield and selectivity, product separation, and safety in operation. Various desirable properties that an effective separator material ideally should exhibit are presented. The chapter discusses four components of modern bilayer membranes on which cell designs are based, such as a thin weak acid cation exchange polymer; a thicker, strong acid polymer; a reinforcing fluorocarbon net in the strong polymer membrane; and a surface coating on the anolyte side of the membrane.