Simple, Low Energy Method Desalinates Seawater

The United Nations estimates that one-third of the global population already lives in water-stressed areas; this figure is expected to double by 2025. Salt water, on the other hand, is not in short supply. A seemingly obvious solution would be to desalinate seawater; however, this is not so easy. Processes like vaporization and subsequent condensation of the water require enormous amounts of energy. Reverse osmosis additionally requires expensive, delicate membranes that are easily fouled, and the water must undergo complex pre-treatment steps.

Developed with the support of the U.S. Department of Energy by Richard Crooks (The Univ. of Texas at Austin), Prof. Ulrich Tallarek (Univ. of Marburg), and their colleagues, the new electrochemical process works without membranes or large amounts of energy. The researchers force the water through a system of two microchannels that are about 22 µm wide, an auxiliary channel and a branched working channel, flowing on to the outlets. The two channels are electrically connected through a bipolar electrode. The auxiliary channel is connected to a voltage source, the working channel is grounded, and a potential difference of 3.0 V is established between the two channels.

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