Seawater desalination with nothing more than a small electrical field? A simple new method of creating freshwater from seawater\u2014that uses far less energy than conventional methods do\u2014has just been developed by researchers at the University of Texas at Austin and the University of Marburg in Germany.<\/p>\n
The new method\u2014electrochemically mediated seawater desalination<\/a>\u2014uses no membranes, is considerably simpler than conventional methods, and is so low-energy that it can be performed with the energy provided by store-bought batteries. Those are big improvements on all fronts\u2014if the process can be adequately scaled up, it\u2019s a potentially revolutionary development. Freshwater scarcity is expected to become a significant problem in many regions of the world in the coming decades, but as it stands now, saltwater desalination isn\u2019t particularly economical \u2026 A cheaper, simpler method than those currently available would be of great use\u2014one which could be used on larger scales than simple solar stills<\/a> are.<\/p>\n The new method\/technology is patent-pending and is currently in commercial development by startup company Okeanos Technologies.<\/p>\n \u201cThe availability of water for drinking and crop irrigation is one of the most basic requirements for maintaining and improving human health,\u201d said Richard Crooks of The University of Texas at Austin. \u201cSeawater 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\u2019ve 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.\u201d<\/p>\n The researchers think that the new method could be of particular use to those in the world\u2019s poorer, more water-stressed regions\u2014more than a third of the world\u2019s people live in such regions. While lacking in freshwater, the majority of these regions have access to vast seawater resources, just not an economical means to desalinate it.<\/p>\n \u201cPeople are dying because of a lack of freshwater,\u201d said Tony Frudakis, founder and CEO of Okeanos Technologies. \u201cAnd they\u2019ll continue to do so until there is some kind of breakthrough, and that is what we are hoping our technology will represent.\u201d<\/p>\n The University of Texas at Austin<\/a> explains the method:<\/p>\n 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 \u201cion depletion zone\u201d 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.<\/p>\n \u201cThe neutralization reaction occurring at the electrode is key to removing the salts in seawater,\u201d stated Kyle Knust, a graduate student and co-author on the new research paper.<\/p>\n \u201cLike a troll at the foot of the bridge, the ion depletion zone prevents salt from passing through, resulting in the production of freshwater.\u201d<\/p>\n As of now, the best that the researchers have achieved is 25 percent desalination\u2014drinking water requires 99 percent desalination. The researchers are confident, though, that the 99 percent goal is very achievable.<\/p>\n \u201cThis was a proof of principle,\u201d stated Knust. \u201cWe\u2019ve 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.\u201d<\/p>\n The process will also need to be scaled up\u2014as of right now, the microchannels are about the size of a human hair, and produce about 40 nanoliters of desalted water per minute. In order for the technology to be of practical use, a device would have to produce several liters\u2014at least\u2014of water per day.<\/p>\n The researchers are confident that this can be achieved, creating \u201ca future in which the technology is deployed at different scales to meet different needs.\u201d<\/p>\n \u201cYou could build a disaster relief array or a municipal-scale unit,\u201d said Frudakis. \u201cOkeanos has even contemplated building a small system that would look like a Coke machine and would operate in a standalone fashion to produce enough water for a small village.\u201d<\/p>\n The new research was just published in the journal Angewandte Chemie<\/i>.<\/p>\n Visit EcoWatch\u2019s WATER<\/a> page for more related news on this topic.<\/b><\/p>\n