Electrochemical processes during polarization of bipolar ion exchange membranes

The elementary processes which control the electrochemical synthesis of hydroxonium and hydroxyl ions on the bipolar membranes are considered in terms of theory of acids and bases in M.I. Usanovich's interpretation. Analogies between the electromembrane processes and the processes on metallic and redox electrodes are traced. It is noted that in terms of electrochemical reaction kinetics the generation of hydroxonium and hydroxyl ions in the bipolar contact zone can be referred both to the cathodic and anodic processes. The corresponding expressions for exchange current, transition overpotential, cathodic and anodic components of current, as well as other kinetic dependences are derived within the stated conception. The total process has three stages, each of them can be limiting, for one brand of the membrane the process proceeding by water oxidation mechanism, for another - by water reduction one.