Billions of people have no access to clean water or must travel great distances to get it. The ability to get  water directly from the air would change their lives. But so far technology generally requires high moisture and a lot of electricity, which is out of reach for much of the world. This problem is now being solved.  Systems are being developed that rely on  energy readily available from the sun and can work even in arid regions—where a third of the world’s population lives, often in poverty.

 

The Massachusetts Institute of Technology and the University of California, Berkeley have tested device that requires no electricity at all.

 

The system works, using a class of porous crystals called metal-organic frameworks (MOFs), developed years ago by chemist Omar M. Yaghi, now in the U.C. Berkeley group. By choosing specific combinations of metals and organics, scientists can select the chemical properties of each MOF and thereby customize its uses. MOFs’ great promise lies with their phenomenally large pores: the surface area inside is almost ten times that of most other porous substances - a MOF crystal the size of a sugar cube has an internal surface area approximately equal to the area of a football field.

 

In April Yaghi and mechanical engineer Evelyn Wang, reported on a prototype device using MOF-801 (zirconium fumarate), which has a high affinity for water. It can operate using only low-grade heat from natural sunlight. The device can produce two quartsof water daily per every 35 ounces of MOF even at relative humidity levels as low as 20%, similar to the humidity of deserts, and it requires no additional input of energy.  Further experimentation with MOF composition should make the technology less expensive (zirconium costs $150 per kilogram), increase the amount of water collected per unit of material and allow researchers to tailor MOFs to different microclimates.

 

Taking a different tack, a start-up called Zero Mass Water in Scottsdale, Ariz., has begun selling a solar-based system that does not have to be hooked up to an electric grid or an existing water system. A solar panel provides energy that both drives air through a proprietary water-absorbing material and powers condensation of the extracted moisture into fluid. A small lithium-ion battery operates the device when the sun is not shining. A unit with one solar panel, the company says, can produce two to five quarts of liquid a day, which is stored in a 7 gallon reservoir that adds calcium and magnesium for health and taste.

 

Cody Friesen, founder of Zero Mass Water and a materials scientist at Arizona State University, developed the system with the aim of having it work sustainably and easily anywhere in the world. An installed system with one solar panel sells in the U.S. for about $3700, including a required 10% donation toward reducing costs for installations in parts of the globe lacking a water infrastructure. The same panel that provides luxury, bottle-free water in the U.S., Friesen notes, can also provide clean water to a school that lacks it so that children “are able to get educated and not get sick.” Over the past year, he says, systems have been placed in the southwestern U.S. and several other countries—among them, Mexico, Jordan and Dubai—and the company has recently shipped panels to Lebanon, with funding from the U.S. Agency for International Development, to provide water to Syrian refugees. When most people think about solar, he adds, “they think about electricity. In the future, people will think about water abundance.”