MIT Engineers Created a Portable Device that Zaps Seawater to Make Drinking Water

Karen Kasmauski
Karen Kasmauski

A team of scientists at MIT have created a device that transforms brackish seawater into clean drinking water at the push of a button—and can be especially helpful for people living in seaside places like California who are dealing with climate change-fueled droughts.

The new desalination device (a term used to describe a machine that can remove salt from seawater) is roughly the size of a suitcase, weighs less than 10 kilograms, and uses less energy than a cell phone charger, according to a paper published on April 14 in the journal Environmental Science and Technology. At a push of a button, can automatically create potable drinking water that exceeds the World Health Organization’s water quality standards.

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“Even a kindergarten student can carry and use the desalination unit,” Junghyo Yoon, a research scientist in the Research Laboratory of Electronics at MIT and co-author of the paper, told The Daily Beast. “[Ease of use] was one of the main motivations of creating the device.”

The device doesn’t rely on any filters like traditional desalination machines. Instead, it zaps the water with electric currents to remove minerals such as salt particles from the water. Due to its portability and the lack of filters that need to be replaced, it has a wide range of applications including being sent to seaside communities, climate catastrophe refugees, or even doomsday preppers, according to Yoon.

“My team and I have been working on desalination technology for more than ten years now,” Jongyoon Han, a professor of electrical engineering and computer science and of biological engineering at MIT and lead author of the paper, told The Daily Beast. “This particular technology went through many different iterations and finally we reached a milestone of a system that can be demonstrated.”

Yoon’s and Han’s new device solves a few issues that plague most commercially-available desalination machines. For one, pushing water via pumps through filters is fairly energy intensive so it’s difficult to create a smaller, portable version of it. Instead, the MIT team’s device relies on a process called ion concentration polarization (ICP), which utilizes an electric field sent through membranes above and below a channel of water. The field repels charged particles and contaminants into a separate channel of water that is discarded. This allows clean, drinkable water to be produced. “We apply an electric field in the water flow and the electricity helps remove the particles like salt in the water,” Yoon explained. “That’s the basic principle of the device’s desalination process.”

The researchers now want to build off of their device in order to improve its production rate and usability. After all, the more water that the device can make at a time, the more people will be able to access potable and safe drinking water. To that end, Yoon plans to launch a startup in the coming years in order to create a viable, commercial desalination device using the ICP technology with the support of MIT.

However, Han said he has broader and more “long-term goals” for his desalination efforts. Specifically, he wants to take a more critical look at reverse osmosis (RO), a process of desalination in which salt water is pushed through a membrane or filter resulting in clean water. “That achieves good enough energy efficiency, but it has significant maintenance requirements and it only operates on a large scale, such as a big plant,” Han said, adding that it’s an inefficient process for places in the world such as California where “the water demand is always fluctuating” and currently, is in dire need of clean, potable water.

<div class="inline-image__caption"><p>The user-friendly unit, which weighs less than 10 kilograms and does not require the use of filters, can be powered by a small, portable solar panel.</p></div> <div class="inline-image__credit">M. Scott Brauer</div>

The user-friendly unit, which weighs less than 10 kilograms and does not require the use of filters, can be powered by a small, portable solar panel.

M. Scott Brauer

“That flux doesn’t work well with a rigid model of desalination that’s employed by an RO plant,” he said. “So I’m thinking about how we can apply more flexible desalination processes, like ICP. That’s a really long-term direction I’m interested in.”

He also explained that he wants to tackle challenges beyond desalination including detecting and removing contaminants in water such as heavy metals and disease-causing pathogens like viruses and bacteria.

“Most of these contaminants are open charge, so technically speaking we have the opportunity to remove a broad spectrum of contaminants such as lead and bacteria,” Han said. “In the future, we want to engineer our system to remove industrial contaminants. Those prospects are very exciting.”

Read more at The Daily Beast.

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