Desalination 'Water Chip' Uses Small Electrical Fields To Convert Saltwater To Drinkable Water
A new "water chip" method of simple water desalination that could bring relief to millions around the globe who lack potable water has been developed by researchers at University of Texas at Austin and the University of Marburg in Germany.
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The new desalination method is much simpler and consumes less energy than other forms of desalination. It is essentially a little water chip that works by creating an electrical field that removes salt from saltwater. It can run on a store-bought battery.
"The availability of water for drinking and crop irrigation is one of the most basic requirements for maintaining and improving human health," said Richard Crooks of The University of Texas at Austin. "Seawater desalination is one way to address this need, but most current methods for desalinating water rely on expensive and easily contaminated membranes. 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."
The University of Texas website explains the science behind the desalination method:
To achieve desalination, the researchers apply a small voltage (3.0 volts) to a plastic chip filled with seawater. The chip contains a microchannel with two branches. At the junction of the channel an embedded electrode neutralizes some of the chloride ions in seawater to create an "ion depletion zone" that increases the local electric field compared with the rest of the channel. This change in the electric field is sufficient to redirect salts into one branch, allowing desalinated water to pass through the other branch.
Put in plain English, the desalination method is the equivalent of a troll at the foot of a bridge: the "ion depletion zone" prevents the salt from passing through. The result is freshwater.
Or almost freshwater. The desalination method currently yields water that is 25 percent desalinated. Drinkable water requires 99 percent desalination. But the researchers are confident they'll be able to get the desalination levels higher.
"This was a proof of principle," said Kyle Knust, a graduate student at the University of Texas who worked on the desalination project. "We've made comparable performance improvements while developing other applications based on the formation of an ion depletion zone. That suggests that 99 percent desalination is not beyond our reach."
According to water.org, 780 million people lack access to drinkable water worldwide, with 345 million lacking access to freshwater in Africa.
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