Electrodialysis

Electrodialysis is an electro-membrane process in which ions are transported through ion permeable membranes from one solution to another under the influence of a potential gradient. Most of the salts dissolved in water are ionic. Therefore desalination of water can easily be carried out since both cations and anions are attracted to electrodes with an opposite electric charge. We can design membranes that permit passage to anions and cations. Electrodialysis require a large amount of electricity to produce a cuurent which is strong enough to manipulate the impurity ions. Limitation of electrodialysis is that it cannot remove organics, pyrogenes and elemental metals. The main components of an electrodialysis unit are saline feed tube, anion and cation selective membranes, negative and positive poles, concentrated brine pipe, fresh water flowing pipe and a fresh water tank. Ion-exchange resins are used as ion permeable membranes.