Effects of temperature and ion transport on water splitting in bipolar membranes

Abstract

We have considered the effects of temperature and ion transport on water splitting in bipolar membranes. The Nernst-Planck equations are employed for the ion fluxes, and the water splitting phenomenon is accounted for by means of either the Onsager theory of the Second Wien Effect or the Chemical Reaction model. Comparison between theory and experiment can be done on the basis of the experimental data by Zabolotskii et al. [Soviet Electrochem., 20 (1985) 1238] . Special attention is paid to the form of the current-voltage curves as well as to the variation of the current carried by the H + and OH − ions with the total electric current. It is found that the predictions derived from the Chemical Reaction model are generally in better agreement with experimental results than those obtained from the Second Wien Effect theory. Finally, we have applied the transport model to a fouled anion exchange membrane exhibiting a bipolar-like structure in order to study the influence of the fixed charge concentration in the fouling film on water splitting.