Energy Efficient Process Discovered to Turn Seawater into Freshwater
Seawater desalination with nothing more than a small electrical field? A simple new method of creating freshwater from seawater—that uses far less energy than conventional methods do—has just been developed by researchers at the University of Texas at Austin and the University of Marburg in Germany.
A prototype "water chip" developed by researchers at The University of Texas at Austin in collaboration with a startup company. Photo Credit: University of Texas at Austin
The new method—electrochemically mediated seawater desalination—uses 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—if the process can be adequately scaled up, it's 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't particularly economical ... A cheaper, simpler method than those currently available would be of great use—one which could be used on larger scales than simple solar stills are.
The new method/technology is patent-pending and is currently in commercial development by startup company Okeanos Technologies.
“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 researchers think that the new method could be of particular use to those in the world's poorer, more water-stressed regions—more than a third of the world's 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.
“People are dying because of a lack of freshwater," said Tony Frudakis, founder and CEO of Okeanos Technologies. “And they'll continue to do so until there is some kind of breakthrough, and that is what we are hoping our technology will represent."
The University of Texas at Austin explains 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.
“The neutralization reaction occurring at the electrode is key to removing the salts in seawater," stated Kyle Knust, a graduate student and co-author on the new research paper.
“Like a troll at the foot of the bridge, the ion depletion zone prevents salt from passing through, resulting in the production of freshwater."
As of now, the best that the researchers have achieved is 25 percent desalination—drinking water requires 99 percent desalination. The researchers are confident, though, that the 99 percent goal is very achievable.
“This was a proof of principle," stated Knust. “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."
The process will also need to be scaled up—as 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—at least—of water per day.
The researchers are confident that this can be achieved, creating “a future in which the technology is deployed at different scales to meet different needs."
“You could build a disaster relief array or a municipal-scale unit," said Frudakis. “Okeanos 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."
The new research was just published in the journal Angewandte Chemie.
Visit EcoWatch's WATER page for more related news on this topic.
SIGN THIS PETITION TODAY:
By Brett Wilkins
One hundred seconds to midnight. That's how close humanity is to the apocalypse, and it's as close as the world has ever been, according to Wednesday's annual announcement from the Bulletin of the Atomic Scientists, a group that has been running its "Doomsday Clock" since the early years of the nuclear age in 1947.
EcoWatch Daily Newsletter
- Scientists Discover New Population of Endangered Blue Whales ... ›
- Endangered Blue Whales Make 'Unprecedented' Comeback to ... ›
- Endangered North Atlantic Right Whale Calves Spotted Off Coast ... ›
- Only 366 Endangered Right Whales Are Alive: New NOAA Report ... ›
By Yoram Vodovotz and Michael Parkinson
The majority of Americans are stressed, sleep-deprived and overweight and suffer from largely preventable lifestyle diseases such as heart disease, cancer, stroke and diabetes. Being overweight or obese contributes to the 50% of adults who suffer high blood pressure, 10% with diabetes and additional 35% with pre-diabetes. And the costs are unaffordable and growing. About 90% of the nearly $4 trillion Americans spend annually for health care in the U.S. is for chronic diseases and mental health conditions. But there are new lifestyle "medicines" that are free that doctors could be prescribing for all their patients.
Taking an unconventional approach to conduct the largest-ever poll on climate change, the United Nations' Development Program and the University of Oxford surveyed 1.2 million people across 50 countries from October to December of 2020 through ads distributed in mobile gaming apps.
- Guardian/Vice Poll Finds Most 2020 Voters Favor Climate Action ... ›
- Climate Change Seen as Top Threat in Global Survey - EcoWatch ›
- The U.S. Has More Climate Deniers Than Any Other Wealthy Nation ... ›
By Tara Lohan
Fall used to be the time when millions of monarch butterflies in North America would journey upwards of 2,000 miles to warmer winter habitat.
A monarch butterfly caterpillar feeds on common milkweed on Poplar Island in Maryland. Photo: Will Parson/Chesapeake Bay Program, (CC BY-NC 2.0)