From Seawater to Consuming Water on the Push of a Button – With No Filters!



Seawater to Drinking Water With No Filters

The user-friendly unit, which weighs lower than 10 kilograms and doesn’t require using filters, may be powered by a small, transportable photo voltaic panel. Credit score: M. Scott Brauer

Researchers construct a conveyable desalination unit that generates clear, clear consuming water with out the necessity for filters or high-pressure pumps.

MIT researchers have developed a portable desalination unit, weighing less than 10 kilograms (22 pounds), that can remove particles and salts to generate fresh drinking water.

The device, which is about the size of a suitcase, needs less power to operate than a cell phone charger. It can also be driven by a small, portable solar panel, which can be purchased online for around $50. It automatically generates drinking water that exceeds World Health Organization (WHO) quality standards. The technology is packaged into a user-friendly device that runs with the push of a single button.

Unlike other portable desalination devices that require water to pass through filters, this unit utilizes electrical power to remove particles from drinking water. Eliminating the need for replacement filters significantly reduces the long-term maintenance requirements.

Two Stage Ion Concentration Polarization Process

The setup includes a two-stage ion concentration polarization (ICP) process, with water flowing through six modules in the first stage then through three in the second stage, followed by a single electrodialysis process Credit: M. Scott Brauer

This could enable the unit to be deployed in remote and severely resource-limited areas, such as communities on small islands or aboard seafaring cargo ships. It could also be used to aid refugees fleeing natural disasters or by soldiers carrying out long-term military operations.

“This is really the culmination of a 10-year journey that I and my group have been on. We worked for years on the physics behind individual desalination processes, but pushing all those advances into a box, building a system, and demonstrating it in the ocean, that was a really meaningful and rewarding experience for me,” says senior author Jongyoon Han, a professor of electrical engineering and computer science and of biological engineering, and a member of the Research Laboratory of Electronics (RLE).

Joining Han on the paper are first author Junghyo Yoon, a research scientist in RLE; Hyukjin J. Kwon, a former postdoc; SungKu Kang, a postdoc at Northeastern University; and Eric Brack of the U.S. Army Combat Capabilities Development Command (DEVCOM). The research has been published online in the journal Environmental Science and Technology.

Filter-free expertise

Commercially obtainable transportable desalination items usually require high-pressure pumps to push water via filters, that are very tough to miniaturize with out compromising the energy-efficiency of the gadget, explains Yoon.

As a substitute, their unit depends on a way referred to as ion focus polarization (ICP), which was pioneered by Han’s group greater than 10 years in the past. Moderately than filtering water, the ICP course of applies {an electrical} area to membranes positioned above and beneath a channel of water. The membranes repel positively or negatively charged particles — together with salt molecules, micro organism, and viruses — as they stream previous. The charged particles are funneled right into a second stream of water that’s finally discharged.

The method removes each dissolved and suspended solids, permitting clear water to cross via the channel. Because it solely requires a low-pressure pump, ICP makes use of much less vitality than different methods.

Seawater to Drinking Water Portable Device

The transportable gadget doesn’t require any substitute filters, which enormously reduces the long-term upkeep necessities. Credit score: M. Scott Brauer

However ICP doesn’t all the time take away all of the salts floating in the course of the channel. So the researchers integrated a second course of, generally known as electrodialysis, to take away remaining salt ions.

Yoon and Kang used machine studying to search out the perfect mixture of ICP and electrodialysis modules. The optimum setup features a two-stage ICP course of, with water flowing via six modules within the first stage then via three within the second stage, adopted by a single electrodialysis course of. This minimized vitality utilization whereas making certain the method stays self-cleaning.

“Whereas it’s true that some charged particles might be captured on the ion alternate membrane, in the event that they get trapped, we simply reverse the polarity of the electrical area and the charged particles may be simply eliminated,” Yoon explains.

They shrunk and stacked the ICP and electrodialysis modules to enhance their vitality effectivity and allow them to suit inside a conveyable gadget. The researchers designed the gadget for nonexperts, with only one button to launch the automated desalination and purification course of. As soon as the salinity degree and the variety of particles lower to particular thresholds, the gadget notifies the consumer that the water is drinkable.

The researchers additionally created a smartphone app that may management the unit wirelessly and report real-time information on energy consumption and water salinity.

Seaside exams

After operating lab experiments utilizing water with totally different salinity and turbidity (cloudiness) ranges, they field-tested the gadget at Boston’s Carson Seaside.

Yoon and Kwon set the field close to the shore and tossed the feed tube into the water. In about half an hour, the gadget had crammed a plastic consuming cup with clear, drinkable water.

Jongyoon Han and Junghyo Yoon

MIT researchers have created a conveyable desalination unit that may robotically take away particles and salts concurrently to generate consuming water. “That is actually the fruits of a 10-year journey that I and my group have been on,” says senior writer Jongyoon Han, proper, pictured with Junghyo Yoon, seated. Credit score: M. Scott Brauer

“It was profitable even in its first run, which was fairly thrilling and stunning. However I believe the primary purpose we had been profitable is the buildup of all these little advances that we made alongside the way in which,” Han says.

The ensuing water exceeded World Well being Group high quality tips, and the unit decreased the quantity of suspended solids by not less than an element of 10. Their prototype generates consuming water at a charge of 0.3 liters per hour, and requires solely 20 watts of energy per liter.

“Proper now, we’re pushing our analysis to scale up that manufacturing charge,” Yoon says.

One of many largest challenges of designing the transportable system was engineering an intuitive gadget that might be utilized by anybody, Han says.

Yoon hopes to make the gadget extra user-friendly and enhance its vitality effectivity and manufacturing charge via a startup he plans to launch to commercialize the expertise.

Within the lab, Han needs to use the teachings he’s realized over the previous decade to water-quality points that transcend desalination, similar to quickly detecting contaminants in consuming water.

“That is positively an thrilling challenge, and I’m happy with the progress we’ve got made to this point, however there may be nonetheless loads of work to do,” he says.

For instance, whereas the “improvement of transportable techniques utilizing electro-membrane processes is an authentic and thrilling course in off-grid, small-scale desalination,” the results of fouling, particularly if the water has excessive turbidity, might considerably improve upkeep necessities and vitality prices, notes Nidal Hilal, professor of engineering and director of the New York University Abu Dhabi Water research center, who was not involved with this research.

“Another limitation is the use of expensive materials,” he adds. “It would be interesting to see similar systems with low-cost materials in place.”

Reference: “Portable Seawater Desalination System for Generating Drinkable Water in Remote Locations” by Junghyo Yoon, Hyukjin J. Kwon, SungKu Kang, Eric Brack and Jongyoon Han, 14 April 2022, Environmental Science and Technology.
DOI: 10.1021/acs.est.1c08466

The research was funded, in part, by the DEVCOM Soldier Center, the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS), the Experimental AI Postdoc Fellowship Program of Northeastern University, and the Roux AI Institute.

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