Transport of Bicarbonate, Carbonate, and Chloride Ions through Ion Exchange Membranes

Abstract

The integral transport numbers of chloride and bicarbonate ions in the commercial anion‐exchange membranes “Permutit 3148,” “AMF 101” (American Machine and Foundry Company) and “Asahi Anionic,” and the concomitant water transport were determined. The cathode compartment contained mixed solutions of sodium bicarbonate and chloride in different proportions and of total normality 0.05. It was found that in all three membranes preferential transport of chloride takes place, that the electroosmotic transport of water with bicarbonate is higher than with chloride and that the electroosmotic water transport varies in the same order as the water content of the chloride forms of the membranes expressed in terms of moles per equivalent Cl−. Competitive transport of carbonate and chloride in “AMF 101” was also measured. The preferential transport of chloride is even more pronounced in this case than in chloride‐bicarbonate systems.