ABSTRACT
This chapter discusses the nature of ion-exchange membranes and the properties which are important to electrodialysis. It describes the processes and apparatus and a specific description of the industrial applications including a discussion of the relevant economics. Ion-exchange membranes are usually reinforced with fabric to give them mechanical strength and contain from 20 to 70% water by weight. The principal commercial application for electrodialysis has been the demineralization of brackish water. The Russian State Committee on Atomic Energy has developed electrodialysis for desalination of the large brackish aquifers which underlie much of southern and south-eastern Russia. In Japan, electrodialysis has been used primarily in production of salt from sea water. The chapter addresses the cost reductions of electrodialysis equipment which have resulted from process simplification and mass production. There are two major factors influencing costs: plant capacity and number of stages.
