This Device Can Produce Drinking Water From Even the Driest Desert Air

Around the world, severe water shortages are becoming increasingly common, and the situation is only expected to worsen as temperatures rise.

In light of this, Massachusetts Institute of Technology (MIT) researchers have created a concept device that can extract moisture from the air and turn it into drinking water, even in the driest places on Earth, potentially providing a solution to the problem of water scarcity in arid climates.

Deserts and other arid regions may seem as though they are completely devoid of water, but there is actually always some moisture in the air. The device has been designed to capture it.

The extractor, which was first proposed last year, was recently field-tested in the dry air of Tempe, Arizona. The research team's work has been described in a new study published in the journal Nature Communications.

The new device can function in relative humidities of as low as 10 percent and is powered solely by sunlight, making it ideal for desert regions. In the absence of sunlight, another heat source—such as a fire—could potentially be used to power the device.

To capture the water, the extractor uses porous, sponge-like materials with large surface areas known as metal-organic frameworks (MOFs)—a family of relatively new and chemically diverse artificial compounds with applications in a wide range of fields, ranging from physics and engineering to biology, chemistry and medicine.

These MOFs, which can be altered to attract water, are placed between an upper black surface, which absorbs heat, and a lower surface kept at the same temperature as the outside air. Water in the air is captured by the MOFs and is then released as water vapor from the pores of the material. This then drips down to the bottom of the device as a liquid, in a process driven by the temperature difference between the higher and lower surfaces.

Deserts and other arid regions may seem as though they are completely devoid of water, but there is actually always some moisture in the air. Researchers at Massachusetts Institute of Technology (MIT) have developed a new device that is able to extract moisture from very dry air. MIT

Methods for harvesting potable water from air already exist, but they require high humidity levels—100 percent humidity for so-called fog-harvesting methods and above 50 percent for dew-harvesting systems.

Unlike these existing methods, the new approach can work in a much wider range of conditions, according to Sameer Rao, an MIT postdoctoral fellow and co–lead author of the new study. Not only can the device function at far lower levels of humidity, it also has no moving parts and doesn't require large amounts of energy for cooling—in contrast to the dew-harvesting method, for example.

Furthermore, during the field experiments for the latest study, the team tested the water produced by the device using a mass spectrometer. It found that it contained no traces of impurities and was safe to drink.

The MIT researchers say the next step is to scale up the system and boost its efficiency to the point where each unit could produce enough water for an entire household.

"We hope to have a system that's able to produce liters of water," said Evelyn Wang, a professor of mechanical engineering and senior author of the latest paper. "These small, initial test systems were only designed to produce a few milliliters, to prove the concept worked in real-world conditions, but we want to see water pouring out!"