IMPROVEMENTS OF THE SELECTIVITY OF IONIC TRANSPORT THROUGH ELECTRODIALYSIS MEMBRANES IN RELATION WITH THE PERFORMANCES OF SEPARATION ELECTROMEMBRANE PROCESSES

Separation electromembrane processes such as electrodialysis or electr o-electrodialysis are being applied to bioindustries and to the treatm ent of industry waste waters. For these purposes, the selectivity of i on transport has to be improved in order to obtain performances of the process which are compatible with the technico-economical conditions. In this paper, we examine four particular cases where the analysis of the ion transport selectivity has been developed in relation with bet ter performances of the electromembrane processes: (i) Reduction of th e proton leakage through anion exchange membranes in contact with acid ic solutions. (ii) Specific transport of protons through cation exchan ge membranes in contact with solutions containing both an acid and a b ivalent metallic ion. (iii) Reduction of cation leakage through bipola r membranes, (iiii) Loss of permselectivity of cation exchange membran es due to the poisoning of the membrane by organic ions