Effect of asymmetry in a bipolar membrane on water dissociation — a mathematical analysis Original Research Article

Based on a simple model established in the previous paper for water dissociation process on a bipolar membrane, this work is concentrated on analyzing the membrane asymmetry on the water dissociation process. Special attention is paid to thickness ratio, fixed group concentration ratio and the water diffusivity ratio of anion layer to cation layer on water concentration, proton or hydroxyl ions concentration in the depletion layer as well as the current density curves. The results suggest that for practical applications, an asymmetric bipolar membrane with the appropriate thickness, proper ion-exchange capacity and high permeability to water will receive more effective results than a symmetric one.