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Researchers at the Massachusetts Institute of Technology have developed a portable desalination device weighing less than 10 kg that removes particles and salt to produce drinking water.
The suitcase-sized device uses less power than a phone charger and can also be powered by a small portable solar panel that can be purchased online for about $50. It automatically produces drinking water that exceeds World Health Organization standards. The technology is packaged in a user-friendly device that works at the push of a button.
Unlike other portable water makers that require water to pass through a filter, this device uses electricity to remove particles from drinking water. Filter replacement is not required, greatly reducing the need for long-term maintenance.
This could allow the unit to be deployed to remote and highly resource-constrained areas, such as communities on small islands or aboard offshore cargo ships. It can also be used to help refugees fleeing natural disasters or soldiers involved in long-term military operations.
“This is really the culmination of a 10 year journey for me and my team. Over the years we have been working on the physics behind various desalination processes, but putting all these advances in a box, building a system and doing it in the ocean. It has been very rewarding and a rewarding experience for me,” said senior author Jongyoon Han, a professor of electrical engineering, computer science, and bioengineering and a member of the Electronics Research Laboratory (RLE).
Khan was joined by first author Jungyo Yoon, RLE Fellow, Hyukjin J. Kwon, former postdoctoral fellow, Sungku Kang, postdoctoral fellow at Northeastern University, and US Army Combat Capabilities Development Command (DEVCOM) Eric Braque. The study was published online in the journal Environmental Science & Technology.
Yoon explained that commercial portable desalination plants typically require high-pressure pumps to drive water through filters, which are difficult to miniaturize without compromising the unit’s energy efficiency.
Instead, their device is based on a technique called ion-concentration polarization (ICP), which Khan’s group pioneered over 10 years ago. Instead of filtering water, the ICP process applies an electric field to a membrane located above and below the waterway. When positively or negatively charged particles, including salt molecules, bacteria and viruses, pass through the membrane, they are repelled from it. The charged particles are directed into a second stream of water, which is eventually ejected.
This process removes dissolved and suspended solids, allowing clean water to pass through the channels. Because it only requires a low pressure pump, ICP uses less energy than other technologies.
But ICP does not always remove all the salt floating in the middle of the channel. So the researchers implemented a second process called electrodialysis to remove the remaining salt ions.
Yun and Kang used machine learning to find the perfect combination of ICP and electrodialysis modules. The optimal setup consists of a two-stage ICP process where water passes through six modules in the first stage, then through three modules in the second stage, followed by an electrodialysis process. This minimizes energy consumption while making the process self-cleaning.
“While it is true that some charged particles can be captured by the ion exchange membrane, if they are trapped, we can easily remove the charged particles by simply changing the polarity of the electric field,” Yun explained.
They shrunk and stowed the ICP and electrodialysis modules to improve their energy efficiency and allow them to fit into portable units. Researchers have developed a device for non-specialists to start the process of automatic desalination and cleaning with just one button. Once the salinity and particle count fall below certain thresholds, the device notifies users that the water is ready to drink.
The researchers also created a smartphone app that wirelessly controls the device and reports real-time data on energy consumption and water salinity.
After laboratory experiments with water of varying degrees of salinity and turbidity (turbidity), the device was tested in the field on Boston’s Carson Beach.
Yoon and Kwon set the box on the bank and dropped the feeder into the water. After about half an hour, the device filled a plastic cup with clean drinking water.
“It was very exciting and surprising that it was successful even at the first launch. But I think the main reason for our success is the accumulation of all these small improvements that we made along the way, ”Khan said.
The resulting water exceeds the quality standards of the World Health Organization, and the installation reduces the amount of suspended solids by at least 10 times. Their prototype produces drinking water at a rate of 0.3 liters per hour and consumes only 20 watt-hours per liter.
According to Khan, one of the biggest challenges in developing a portable system is to create an intuitive device that anyone can use.
Yoon hopes to commercialize the technology through a startup he plans to launch to make the device more user-friendly and improve its energy efficiency and performance.
In the lab, Khan wants to apply the lessons he has learned over the past decade to water quality issues beyond desalination, such as the rapid detection of contaminants in drinking water.
“It’s definitely an exciting project and I’m proud of the progress we’ve made so far, but there’s still a lot of work to be done,” he said.
For example, while “development of portable systems using electromembrane processes is an original and interesting avenue for off-grid small-scale water desalination,” the effects of pollution, especially if the water has high turbidity, can significantly increase maintenance requirements and energy costs, notes Nidal Hilal, Prof. engineer and director of the Abu Dhabi Water Research Center at New York University, who was not involved in the study.
“Another limitation is the use of expensive materials,” he added. “It will be interesting to see similar systems using inexpensive materials.”
The study was funded in part by the DEVCOM Soldier Center, the Abdul Latif Jameel Water and Food Systems Laboratory (J-WAFS), the Northeastern University Postdoctoral Fellowship Program in Experimental Artificial Intelligence, and the Ru Institute of Artificial Intelligence.
Researchers at MIT’s Electronics Research Laboratory have developed a portable watermaker that can turn seawater into safe drinking water, according to Fortune’s Ian Mount. Mount writes that research scientist Jongyun Khan and graduate student Bruce Crawford founded Nona Technologies to commercialize the product.
Researchers at the Massachusetts Institute of Technology “have developed a free-floating desalination device consisting of multiple layers of evaporators that recover heat from the condensation of water vapor, increasing its overall efficiency,” Neil Nell Lewis of CNN reports. “The researchers suggest that it could be configured as a floating panel at sea, piped fresh water to shore, or it could be designed to serve a single household using it in a seawater tank,” Lewis wrote.
MIT researchers have developed a suitcase-sized portable desalination device that can turn salt water into drinking water at the push of a button, reports Elisaveta M. Brandon of Fast Company. The device could be “an essential tool for people on remote islands, offshore cargo ships, and even refugee camps close to water,” Brandon wrote.
Motherboard reporter Audrey Carlton writes that MIT researchers have developed “a filterless, portable desalination device that uses solar-generated electric fields to deflect charged particles such as salt, bacteria and viruses.” Scarcity is a growing problem for everyone due to rising sea levels. We don’t want a bleak future, but we want to help people be prepared for it.”
A new portable solar-powered desalination device developed by MIT researchers can produce drinking water at the touch of a button, according to Tony Ho Tran of The Daily Beast. “The device does not depend on any filters like conventional watermakers,” Tran wrote. “Instead, it electrocutes the water to remove minerals, such as salt particles, from the water.”