MIT creates portable, low-powered desalinator

Posted by Staff writer

MIT and Korean researchers have developed a portable desalinator that could supply a small village using solar power.

The device is based on a new approach to desalination, called ion concentration polarization. It works at a microscopic scale, using fabrication methods developed for microfluidics devices.

The widgets only process minute amounts of water, but the researchers envision an array with 1,600 units fabricated on an eight-inch wafer. This, they say, could produce about 15 liters of water per hour.

The whole unit could be self-contained and driven by gravity — salt water would be poured in at the top, and fresh water and concentrated brine collected from two outlets at the bottom.

So far, the researchers have successfully tested a single unit, using seawater they collected from a Massachusetts beach and then contaminated with small plastic particles, protein and human blood.

The unit removed more than 99 percent of the salt and other contaminants. “We clearly demonstrated that we can do it at the unit chip level,” says MIT's Sung Jae Kim.

While the technique requires slightly more electricity than present large-scale methods such as reverse osmosis, there's no other method that can produce small-scale desalination with anywhere near this level of efficiency, the researchers say.

If properly engineered, the proposed system would only use about as much power as a conventional lightbulb, and could run on solar power, they say.

The team now plans to produce a 100-unit device to demonstrate the scaling-up of the process, followed by a 10,000-unit system. They expect it will take about two years before the system will be ready to develop as a product.