Influence of the heterogeneous structure on the electrochemical properties of anion exchange membranes

In this study, the influence of the degree of the heterogeneity on the electrochemical behaviors was investigated for commercial anion exchange membranes using three monovalent organic electrolytes with sodium form (acetate, D-gluconate and monovalent citrate), which can be produced from fermentation processes, and an inorganic electrolyte (NaCl). As indicators of the heterogeneity for anion exchange membranes, the fraction of the inter-gel phase and the conducting phase in the membrane structure were considered in this study. Using the isoconductance value of an anion exchange membrane, the diffusion coefficient through the joint-gel phase in the membrane structure showed the sequence of chloride > acetate > gluconate > monovalent citrate. The fraction of the inter-gel phase of the heterogeneous membranes was much higher than that of the homogeneous membranes due to the heterogeneous structure. In addition, the fractions of conducting phase of heterogeneous membranes were estimated as much lower than those of homogeneous membranes. It was shown in the study that the heterogeneous structures affected the electrochemical properties of anion exchange membranes, which were characterized by the chronopotentiometry and the current-voltage relationship. (c) 2008 Elsevier B.V. All rights reserved.