In recent years

the electrodeionization(EDI)and some integrated processes derived from EDI play important roles in some fields such as desalination

ion concentrating and chemical synthesis

but it is still needed to explore the mechanism of water decomposition at the membrane-liquid interface of ion-exchange membranes.In this study

the degradation of anion exchange membrane in EDI process and its effects on water decomposition were examined and analyzed through experiments.The phenomenon of partial degradation of the anion exchange membrane from quarternary ammonium to tertiary amine is confirmed through the tests for permselectivity

exchange capacity

conductivity and infrared spectroscopy analysis.Furthermore

based on the investigation on the characteristic curves of the EDI process

it is validated that the weakly basic tertiary amine group has a catalytic effect on the water decomposition at the membrane-solution interface of the anion exchange membrane.The results are helpful for the design and improvement of the EDI and EDI-based electro-membrane processes

so that the water decomposition can be well controlled to achieve some specific separation.