This Portable, Solar-Powered Device Purifies Seawater on Demand

Good News Notes:

Imagine having the ability to purify water anywhere, any time, with one solar-powered device. While that may not be of key importance to many in wealthy nations, it is for the 785 million people around the world who, as of 2017, lacked access to clean drinking water.

A group of researchers at the Massachusetts Institute of Technology have created a filter-less portable desalination device that uses an electrical field generated by solar energy to repel charged particles like salt, bacteria, and viruses. 

“All indicators tell us that water scarcity is a growing problem for everyone due to rising sea levels,” Junghyo Yoon, first author on the study, told Motherboard in an email. “We don’t hope for a grim future, but we want to help people be prepared for it.” 

The device is the result of 10 years of work, per a press release published by MIT. Dr. Jongyoon Han, senior author on the paper and professor of Electrical and Biological Engineering at MIT, first came up with Ion Concentration Polarization (ICP), the purification technique that the device relies on in 2012, and has since developed it for use forsalty brines from fracking waste and for liquids that contain non-salt contaminants and heavy metals

“Our process does not push water through a membrane,” Bruce Crawford, graduate student at the MIT Sloan School of Management who did not co-author the study but who is a commercialization partner to the study’s first author Junghyo Yoon, said in an email to Motherboard. “Without pushing water through a membrane, we eliminate the possibility for membrane clogging and fouling, and we can operate with super low power draw, which means our devices can be way smaller than incumbent devices and use way less electricity.”

Han and his teams’ most recent finding, published last week in the journal Environmental Science and Technologytakes this process and applies it to a portable device around the size of a carry-on suitcase. Unlike other industrial desalination processes, like reverse osmosis—a centuries-old technology in which pressure is used to push water through a semipermeable membrane, like a filter or net that removes contaminants—ICP can be used at a small scale in remote settings and does not require the use of replacement filters.  

“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,” Han said in a release…..”

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