Anion-exchange membranes with improved alkaline stability

With the increasing use of electrodialysis in the chemical and biochemical process industry and for the treatment of industrial waste waters, the demand for ion-exchange membranes which provide good stability in strong acid or alkaline solutions has drastically increased. Cation-exchange membranes with adequate chemical stability are available today. However, all commercial anion-exchanges are unsatisfactory as far as their alkaline stability is concerned. In this paper the development of anion-exchange membranes with low electrical resistance, high selectivity and good long-term stability in strong alkaline solutions is described.