Researchers find a new way to make water from air

The current MOF can absorb only 20 per cent of its weight in water, but other MOF materials could possibly absorb 40 per cent or more. These compounds feature a combination of metals that are stitched together with organic molecules in a tinker-toy arrangement.

MOFs have been used for many different applications in the past, including gas storage, dehumidification and the capture of carbon dioxide emissions.

The two main researchers at Berkeley and MIT who were behind the invention are Evelyn Wang, an associate engineering professor at MIT, and Omar Yaghi, a chemist at the University of California, Berkeley.

"Upon heating by ambient sunlight, the water is released from the pores and condensed as a result of the temperature difference between the material in the device and the surroundings".

The system proposed by Yaghi uses sunlight without any additional power source, although water can only be collected throughout the day.

To create the device, researchers developed a zirconium-based material that binds water vapor.

The technology is a long way from being ready for commercial use, but the team behind it says this breakthrough has laid the groundwork for a device that could deliver potable water to many parts of the world. Not so with a MOF device. "It will have a tremendous scientific and technical impact on renewable and sustainable resources, such as water and solar energy".

The device pulls 2.8 liters of water out of the atmosphere per day for each kilogram of MOF it contains.

But it's just a prototype. "So the amount of water that we've shown is also pretty small", says Wang. "That can give you a household of water per four people per day". "Even within the next couple of years once we scale up the material", she said.

An illustration of the structure of MOF-801, a MOF design that's been optimized specifically to capture water at low relative humidity.

"We wanted to demonstrate that if you are cut off somewhere in the desert, you could survive because of this device", says Yaghi.

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In a new meta-analysis published in PLOS One, researchers from Purdue, Stanford and the Canadian Council on Animal Care look at the different techniques used to induce laughter in rats in order to improve their wellbeing and capture their laughter, which is delightful.

Imagine a future in which every home has an appliance that pulls all the water the household needs out of the air, even in dry or desert climates, using only the power of the sun.

PALCA: And where is all that water?

There's fresh water hiding in the air we breathe. The problem is it's hard to get at.

Yaghi is the inventor of the metal-organic framework (MOF), a tiny grid made of aluminum or magnesium mixed with organic molecules. "Where the composition of organic and inorganic and the balance between these two allows you to craft the interior so that it loves water, but it doesn't hold onto it too tightly".

Professor Omar Yaghi, one of the senior scientists on the project, is calling the harvester "personalized water". And there are very expensive ways of removing moisture from drier air.

At $150/kg, zirconium is too expensive to use for a mass-produced product meant to be distributed to people living in arid environments, but Yaghi proposes further work that would swap in aluminum, which costs 1% of the cost of zirconium.

  • Joey Payne