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 electro-electrodialysis are being applied to bioindustries and to the treatment of industry waste waters. For these purposes, the selectivity of ion 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 better performances of the electromembrane processes: (i) Reduction of the proton leakage through anion exchange membranes in contact with acidic solutions. (ii) Specific transport of protons through cation exchange membranes in contact with solutions containing both an acid and a bivalent metallic ion. (iii) Reduction of cation leakage through bipolar membranes, (iiii) Loss of permselectivity of cation exchange membranes due to the poisoning of the membrane by organic ions