There seems to have been a very promising breakthrough on a new method for desalinating water announced in the past week or so. I’d seen an article describing this, “New Invention Makes Ocean Water Drinkable”, referenced on Facebook yesterday, which is quite exciting in its possible implications. As that article points out: “an estimated 780 million people across the globe do not have access to drinkable water” nearly half of which reside in the always-troublesome continent of Africa … and there are widespread needs of fresh water for agricultural purposes around the globe.
This new approach, called electrochemically mediated seawater desalination (EMSD), uses what is being described as a “water chip”. The research on this was done at the University of Texas at Austin and the University of Marburg in Germany. A release from the University of Texas describes the 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.
Currently the system is only in the “proof of concept” stage, and achieving around 25% desalination for a rather tiny “40 nanoliters of desalted water per minute” through a channel about the size of a human hair … but the researchers are convinced that they can refine the process to achieve the needed 99% desalination for potable water
While the scientists are currently working on scaling the process up to a “Coke machine sized” device that could provide fresh water for a village, the ultimate impact, should this process be scalable to millions of gallons a day, would be to provide coastal areas with insufficient fresh water (Los Angeles, for example, which uses much of the water supplies of the entire southwest) with entirely new sources of water for both basic urban needs and agriculture. Not only would fresh drinking water come to large parts of the world, but regions that are presently desert could be irrigated and turned into farmland to help feed the planet.
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Filed under: Green Tech Articles