UTA-Marburg desalination research paper published
A paper on the technique termed Electrochemically Mediated Seawater Desalination, now being developed as the WaterChip by US start-up company Okeanos Technologies, was published on 16 June 2013 in the journal Angewandte Chemie (Wiley).The technique, reported a year ago in D&WR, is described as "membraneless" desalination.
A simple power supply is used to apply a 3.0 V potential bias across a microelectrochemical cell comprising two microchannels spanned by a single bipolar electrode (BPE) to drive chloride oxidation and water electrolysis at the BPE poles. The resulting ion-depletion zone and associated electric field gradient direct ions into a branching microchannel, consequently producing desalted water.
The technology was developed by chemists at the University of Texas at Austin (UTA) in the USA and the University of Marburg in Germany. The team was led by Richard Crooks of UTA and Ulrich Tallarek of Marburg.
Thus far Crooks and his colleagues have achieved 25% desalination, the first time this mark has been published. Although drinking water requires 99% desalination, they are confident that goal can be achieved.
"This was a proof of principle," said Kyle Knust, a graduate student in Crooks' lab and first author on the paper. "We've made comparable performance improvements while developing other applications based on the formation of an ion-depletion zone. That suggests that 99% desalination is not beyond our reach."
"Most current methods for desalinating water rely on expensive and easily contaminated membranes," said Crooks, the Robert A Welch chair in Chemistry in the College of Natural Sciences. "The membrane-free method we've developed still needs to be refined and scaled up, but if we can succeed at that, then one day it might be possible to provide fresh water on a massive scale using a simple, even portable, system."