We’re closer than ever before to producing clean water from thin air


water harvester

Scientists from the University of California, Berkeley have developed a device that can harvest fresh water out of the air, even in a dry desert.

The device uses a substance called a metal-organic framework, or MOF, that acts like a sponge to suck moisture out of the air.
While the device is only a small prototype, the scientists behind the project said it could be “scaled up quickly.”

Scientists have figured out a way to harvest water from dry desert air using only the sun’s heat. The device could be a game-changer for the approximately 2.1 billion people around the world who lack immediate access to clean drinking water.

The device is made of a porous material called a metal-organic framework (MOF) that’s housed within a clear plastic box. In simple terms, water vapor from the atmosphere condenses on the MOF material, which absorbs it like a sponge. As the water evaporates, it gets trapped and collected by the device.

The group of scientists at the University of California, Berkeley who created the device tested a proof-of-concept last year, then recently tried a prototype out in Scottsdale, Arizona.

The device produced around 7 ounces of water after the researchers left it outside for one full day and night. While that’s not enough to hydrate you, the researchers said in a video posted by UC Berkeley that it’s relatively easy to scale up the device.

The scientists published the results of their field trial in the journal Science Advances last week.

“There is nothing like this,” Omar Yaghi, one of the authors of the report, told Phys.org. “This laboratory-to-desert journey allowed us to really turn water harvesting from an interesting phenomenon into a science.”

How the technology works

The MOF material is made up of metal- and carbon-based organic molecules, and is designed to have many tiny pockets of air between the different types of molecules.

That plethora of small cavities allows the MOF to have a relatively enormous surface area on which moisture from the air can condense. That makes the material super effective at absorbing liquids.

The MOF therefore acts like a sponge, soaking moisture from the air.

It’s easier for the device to absorb water vapor from the air at night, when the relative humidity — the percentage of water vapor in the air as a function of the temperature — is high. Relative humidity generally increases at night because the dew point, the temperature at which a given air mass can no longer hold water vapor, remains the same regardless of what temperature it is outside.

So the MOF absorbs water at night, then when the sun rises in the morning, its heat causes the water to evaporate out of the sponge-like material. But because the device is enclosed in a box, the vapor collects and becomes liquid water again, then drips down into a collection area where it can be used for drinking or any other purpose.

The most efficient water-harvesting solution

Some similar water-harvesting devices already exist. …read more

Source:: Business Insider

      

(Visited 30 times, 1 visits today)

Leave a Reply

Your email address will not be published. Required fields are marked *