Explained: A portable device that turns seawater into drinking water, without using filters

While other portable desalination units that require water to pass through filters, this device utilises electrical power to remove particles from drinking water. Eliminating the need for replacement filters greatly reduces the long-term maintenance requirements. This, the release said, could enable the unit to be deployed in remote and severely resource-limited areas. It could also be used to aid refugees fleeing natural disasters or by soldiers carrying out long-term military operations, it said.

The researchers have described the device in the American Chemical Society journal Environmental Science & Technology.

“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,” the release quoted senior author Jongyoon Han, a professor of electrical engineering and computer science and of biological engineering, as saying.

HOW IT WORKS: The unit relies on a technique called ion concentration polarisation, which was pioneered by Han’s group more than 10 years ago, the release said. Rather than filtering water, the process applies an electrical field that causes positively or negatively charged particles — including salt molecules, bacteria, viruses — to be repelled as they flow past. The charged particles are funnelled into a second stream of water that is eventually discharged. The process removes solids, allowing clean water to pass through the channel.

PAPER: ‘Portable Seawater Desalination System for Generating Drinkable Water in Remote Locations’, Junghyo Yoon et al, Environmental Science & Technology. pubs.acs.org/doi/10.1021/acs.est.1c08466

Source: MIT News