New device can extract water from even the driest desert air

Researchers at the Massachusetts Institute of Technology (MIT) have created a new device that can extract water out of dry air. The potential of the instrument has already been demonstrated, and the experts say that they will now be working to scale up the process.

The system is based on relatively new high-surface-area materials called metal-organic frameworks (MOFs). It was designed to extract potable water from even the driest desert conditions.

The concept was initially described last year in the journal Science, and senior author Evelyn Wang said that the paper drew a lot of attention.

“It got a lot of hype, and some criticism,” she said. But now, “all of the questions that were raised from last time were explicitly demonstrated in this paper. We’ve validated those points.”

A small version of the device that was tested on a rooftop at Arizona State University proved that the extraction system can work even in subzero dewpoints powered by nothing but sunlight.

The researchers explained that, if the device was scaled up, its output would be equivalent to more than a quarter-liter of water per day per kilogram of MOF.

Dew-harvesting systems that are currently in use require 50 percent humidity, and fog-harvesting methods require 100 percent humidity. Remarkably, the new system can work with relative humidity as low as 10 percent.

According to Wang, the next step is to work on scaling up the system and boosting its efficiency.

“We hope to have a system that’s able to produce liters of water.” The small test systems were only designed to produce a few milliliters of water, but Wang says “we want to see water pouring out!”

The water extracted by the system was tested for impurities and no traces were found. Further testing showed that “there’s nothing from the MOF that leaches into the water. It shows the material is indeed very stable, and we can get high-quality water,” said Wang.

Ultimately, the team would like to produce systems that can supply water to individual households.

The study is published in the journal Nature Communications.

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By Chrissy Sexton, Earth.com Staff Writer