ORIGIN AND ELIMINATION OF WATER SPLITTING IN ION-EXCHANGE MEMBRANES DURING WATER DEMINERALIZATION BY ELECTRODIALYSIS

Water splitting in anion exchange membranes containing quaternary ammonium groups is due to the presence of tertiary alkyl amino groups in the surface regions. It may be eliminated by methylation, however it reappears during current flow because quaternary ammonium groups in the surface regions are then converted to the tertiary form. The quaternary ammonium groups are more stable in Negev Institute A than in AMF A1OO membranes. By contrast water splitting is not manifested by cation exchange membranes with sulphonic acid groups if the system is sufficiently clean. © 1979.