An easy switch from seawater to drinking water

Researchers at MIT have built a portable desalination equipment that can remove particles and salts to produce drinking water.?The suitcase-sized device can also be powered by a small, portable solar panel, which can be purchased online for roughly $50. It automatically produces water that meets or surpasses WHO requirements. The technology is bundled into an easy-to-use device.

Unlike other portable desalination systems, this one uses electricity to remove particulates from water. The absence of filter change decreases long-term maintenance requirements. This may allow the unit to be deployed in remote and resource-limited places, such as small island communities or onboard cargo ships. It might potentially be used to help refugees fleeing natural disasters or warriors on long-term missions.

High-pressure pumps are used in commercial portable desalination systems, which are difficult to miniaturize without losing energy efficiency. Instead, they use an ICP approach developed by Han's group over a decade ago. It works by applying an electrical field to membranes above and below a water channel rather than filtering it. Passing salt molecules, bacteria, and viruses are repelled by the membranes' charged particles. The second stream of water is used to discharge the charged particles.

The procedure eliminates dissolved and suspended particles, allowing clean water to flow. ICP saves energy because it just requires a low-pressure pump. But ICP does not always remove all salts from the channel. So the team used electrodialysis to remove any residual salt ions.

Yoon and Kang employed machine learning to discover the best ICP and EDM mix. Two-stage ICP with six modules in the first stage and three in the second stage, followed by electrodialysis. This reduced energy consumption while maintaining self-cleaning.

They stacked and reduced the ICP and electrodialysis modules to save energy and make them portable. The device is simple to use, with only one button to start the desalination and purification process. The device notifies the user when the salinity and particle count are below certain levels.

The team also designed a smartphone app that can wirelessly manage the unit and display real-time power consumption and water salinity.

They field-tested the gadget in Boston's Carson Beach after testing it in the lab with various salinities and turbidities.

Yoon and Kwon threw the feed tube into the water. The device filled a plastic cup with clear, drinkable water in about 30 minutes.

The produced water exceeded WHO quality standards and the unit decreased suspended particles by a factor of 10. Their prototype produces 0.3 liters of water every hour at 20 watts per liter.

Han believes one of the main problems in building the portable system was making it user-friendly.

The device will be more user-friendly, more energy efficient, and produce more through a firm Yoon will develop to commercialize the concept.

In the lab, Han hopes to use the knowledge he's gained over the last decade to quickly detect toxins in drinking water.

"This is an interesting initiative, and I am proud of our success so far, but there is much more to accomplish," he says.

A grant from the DEVCOM Soldier Center, the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS), Northeastern University's Experimental AI Postdoc Fellowship Program, and the Roux AI Institute helped fund the project.

References:

Yoon, J. H., Kwon, H. J., Kang, S. K., Brack, E., and Han, J. Y. 2022. Portable Seawater Desalination System for Generating Drinkable Water in Remote Locatins. Environmental Science & Technology; DOI 10.1021/acs.est/1c09466

Massachusetts Institute of Technology. (2022, April 28). From seawater to drinking water, with the push of a button: Researchers build a portable desalination unit that generates clear, clean drinking water without the need for filters or high-pressure pumps. ScienceDaily. Retrieved May 8, 2022 from www.sciencedaily.com/releases/2022/04/220428152229.htm