Features of feed concentration and temperature effects on membranes operation in electrodialysis systems – a review

Electrodialysis (ED) is a significant method in saline water desalination and industrial wastewater treatment. Ion exchange membranes (IEMs) are an important part of the electrodialysis process. An ion-exchange membrane is a semipermeable membrane that transports ions through an oppositely charged membrane and blocks the passage of a co-ion under an electric field. This review describes the effects of feed concentration and its operating temperature on different sides of IEMs in an electrodialysis system. The influence of feed solutions and temperature gradients on diffusion and osmatic membrane permeability was clarified. The distribution of feed concentration under thermostatic and thermodynamic conditions are also discussed. Temperature changes in ED systems may increase ion transport selectivity and charge separation efficiency. The rate of ions transport depends on the number of ions diffusion toward the membrane. To date, there are very few studies reporting diffusion and osmatic permeability of IEMs at high temperature. (paper)