[In46] Electrodialysis

AUTHOR: Marcos Zotes López


Scenario Games: Action Plan: External:

Manufacturers; Industry;
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.
Electrodialysis with bipolar membranes consists of an anion and a cation permeable membrane laminated together. When this composite structure is oriented such that the cation-exchange layer faces the anode it is possible, by imposing a potential field across the membrane, to spit water into proton and hydroxyl ions. This results in the production of acidic and basic solutions at the surfaces of the bipolar membranes. Multiple bipolar membranes along with other ion permeable membranes can be placed between a single pair of electrodes in an electrodialysis stack for the production of acid and base from a neutral salt.
There are substantial advantages to water splitting with bipolar membranes. Since there are no gases evolved at the surface or within the bipolar membranes, the energy associated with conversion of water to O2 and H2 is saved, and the power consumption is about half that of electrolytic cells. Compared to the electrodes used in conventional electrolytic cells, the bipolar membranes are inexpensive. Where dilute acids or bases are needed, bipolar membranes offer the prospect of low cost and minimum unwanted byproducts.