Chapter 8 Water Dissociation

Abstract

Publisher Summary This chapter discusses the water dissociation. Water dissociation reaction is related with the auto-catalytic nature of the functional groups in the membrane. The difference between water dissociation phenomenon of a cation exchange membrane and that of an anion exchange membrane is closely related with the catalytic nature. The chapter provides an overview of the diffusional model. In the repulsion zones the repulsive forces exerted by the fixed membrane charges upon co-ions dominate the situation. Outside the repulsion zones, the rest of the solution boundary layers are present, and outside the boundary layers is the bulk solution phase. The membrane surface potential is equivalent to the space charge and the repulsion zone, and supplies counter-ions from the solution phase toward the membrane phase at an over limiting current. The Wien effect is the phenomenon generated in an electrolyte solution under very strong electric potential fields. The chapter also discusses protonation and deprotonation reactions; and hydrolysis of magnesium ions. The chapter outlines the mechanism of water dissociation.