(Reverse) electrodialysis

Electrodialysis can be used for separating salt from mixed wastewater (which contains both salts and organic pollutants). Two streams (a diluted stream, generally the water to be treated and a concentrated stream, where the salts end up) are contacted to each other in different flow channels, separated on one side by a cation exchange membrane (CEM) and on the other side by an anion exchange membrane (AEM). By using a direct current potential difference, cations move through the CEM to the cathode, whilst anions move to the anode, thus desalinating the water to be treated.