MIT scientists have created a desalination device that can turn seawater into drinking water with a simple button press.

The 10kg portable desalination unit can remove particles and salts to generate drinking water, whilst requiring less power to operate than a cell phone charger.

It automatically generates drinking water that exceeds World Health Organisation (WHO) quality standards, according to the researchers. Unlike other portable desalination units that require water to pass through filters, this device makes use of electrical power to remove particles from drinking water.

The use of this technology removes the need for replacement filters, which reduces the the need to for long-term maintenance and turns seawater into drinking water.

Researchers said this could enable the unit to be deployed in remote areas and countries struggling for resources, especially as climate change begins to affect the planet.

Communities on small islands or aboard seafaring cargo ships and refugees fleeing natural disasters or war could be direct beneficiaries of the tech.

Senior author of the research paper Jongyoon Han, a professor of electrical engineering and computer science and of biological engineering, commented: “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.”

First author Junghyo Yoon, a research scientist in RLE, explains that portable desalination units typically require high-pressure pumps to push water through filters. These are usually very difficult to miniaturise without compromising device energy-efficiency.

However, the researchers have said the new unit relies on a technique called ‘ion concentration polarisation’ (ICP), created by the group more than 10 years ago.

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Rather than filtering water, the ICP process applies an electrical field to membranes placed above and below a channel of water, they said. The membranes repel positively or negatively charged particles — including salt molecules, bacteria, and viruses — as they flow past.

The charged particles are then funnelled into a second stream of water that is discharged. The process removes both dissolved and suspended solids, allowing clean water to pass through the channel.

“While it is true that some charged particles could be captured on the ion exchange membrane, if they get trapped, we just reverse the polarity of the electric field and the charged particles can be easily removed,” Yoon adds.

They shrunk and stacked the ICP and electrodialysis modules to improve their energy efficiency and enable them to fit inside a portable device.

Researchers added that the device is designed for ‘nonexperts’, creating a smartphone app that can control the unit wirelessly and report real-time data on power consumption and water salinity.

Yoon hopes to make a more user-friendly version of the device in the future, whilst improving its energy efficiency and production rate through a new startup.

In the lab, Han said he aims to apply the lessons he’s learned over the past decade to water-quality issues that go beyond desalination, such as rapidly detecting contaminants in drinking water.

“This is definitely an exciting project, and I am proud of the progress we have made so far, but there is still a lot of work to do,” he said.

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