In general, removing salts from water is an expensive, energy intensive process. But a team of chemists at the University of Texas at Austin and the University of Marburg in Germany are developing a new method to produce freshwater from briny that doesn’t involve reverse osmosis or thermal desalination. A small electrical field does the trick.
As UT Austin states, researchers apply 3.0 volts to a plastic chip filled with seawater. The chip has a microchannel with two branches, and an electrode placed at the fork. The electrode neutralizes some of the chloride ions in the water, changing the electric field nearby by creating an “ion depletion zone.” This funnels the salts into one branch, leaving the desalinated water to flow into the other.
Electrochemically mediated seawater desalination, as it’s called, is in the early stages of development. The prototype chip only removes about 25 percent of salts from water in testing and only produces about 40 nanoliters of desalinated water per minute. The chemists developing this technology say that with further research this can be scaled up from its current nanoscale size and 99 percent desalination--the amount necessary to produce drinking water--may be achieved.
image via University of Texas at Austin
written by Jannifer, July 23, 2013
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