Materials

Harvester pulls record amount of drinking water out of thin air

Harvester pulls record amount ...
From left, researchers on the study Zhiyong Xia, Matthew Logan and Spencer Langevin
From left, researchers on the study Zhiyong Xia, Matthew Logan and Spencer Langevin
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From left, researchers on the study Zhiyong Xia, Matthew Logan and Spencer Langevin
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From left, researchers on the study Zhiyong Xia, Matthew Logan and Spencer Langevin
A diagram demonstrating how the metal-organic framework (MOF) captures water from thin air
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A diagram demonstrating how the metal-organic framework (MOF) captures water from thin air

Clean water is all around us, and more literally than you might think – it's floating around in the air most of the time. Of course, it’s not particularly drinkable in that form, but now researchers at the Johns Hopkins Applied Physics Lab (APL) have found materials that can collect huge amounts of water from the air.

As is the case with similar systems we've covered previously, the key lies with a material called a metal-organic framework (MOF). These structures have the highest surface area of any known material – in fact, if you were able to unfold just one gram of an MOF, it would be enough to cover a football field. And all that internal space makes them perfect for capturing and storing water.

Plenty of previous studies have managed to use MOFs to absorb water vapor from the air and collect it in liquid form for drinking. Results have varied, from 100 ml of water per kilogram of MOF used with a UC Berkeley design in 2018, to over 1.3 L (0.3 gallons) per day per kg. But the new system smashes this record.

“We identified a MOF that could produce 8.66 liters (2.3 gall) of water per day per kilogram of MOF under ideal conditions, an extraordinary finding,” says Zhiyong Xia, co-lead author of the study. “This will help us deepen our understanding of these materials and guide the discovery of next-generation water-harvesting methods.”

A diagram demonstrating how the metal-organic framework (MOF) captures water from thin air
A diagram demonstrating how the metal-organic framework (MOF) captures water from thin air

To create this better-performing new version, the team studied 10 different types of MOFs, examining which properties made them more effective. They also investigated how different environmental conditions, such as temperature and humidity, affected their ability to absorb water vapor.

The team plans to continue looking into other types of MOFs and how they could be combined and configured, to see if this system could work more efficiently, and perhaps in drier conditions. After all, that's where potable water is most desperately needed.

The research was published in the journal Scientific Reports. The team describes the work in the video below.

Extracting Water from Thin Air

Source: Johns Hopkins Applied Physics Lab

14 comments
Nobody
What air velocity, pressure, temperature and relative humidity are they extracting the moisture from? Without this information, these efficiency claims are almost worthless.
ljaques
In limited quantity, this could be good for arid areas. But if it's put into widespread use, what effect will it have on the surrounding flora and fauna? If it dries out the area, will beneficial insects go away, leaving only harmful insects? Will it dry out beneficial organisms' food sources, etc? I hope they research that before everyone puts up their own collector, or huge farms collect for huge cities.
Cryptonoetic
Read the study. It's all there.
fredricwilliams
Nobody -- since the article says "ideal conditions" one might reasonably conclude that the state result would require such things as high humidity -- and no claim of "efficiency' is made, only a level of output which may be a maximum. All this is relevant only in relation to amounts previously achieved.
buzzclick
Taking this technology further, could it become a less complicated and more inexpensive way to desalinate sea water? Getting fresh, potable water from the ocean on a feasibly massive scale is becoming more and more crucial.
AlBanting
From the article referenced above, "The adsorption cycle was performed on activated MOFs over 24 h at 70% RH and 22 °C."
Philip Argy
With the recent high humidity in Sydney this kind of technology could have been put to productive use! I've often wondered why people don't harvest the condensate from their air conditioning systems too.
Wombat56
More from the actual research article: "The adsorption cycle was performed on activated MOFs over 24 h at 70% RH and 22 °C. In comparison, the desorption was performed at 30% RH and 60 °C to simulate conditions that can easily be achieved for a thermal-mediated desorption process with little to no energy input." That kind of temperature could be achieved from solar heating with little effort. FWIW the Saharan Desert can have a RH of 40% during the night even if it's only 7% to 10% RH during the day time.
roddy6667
I have followed the water-from-the-air developments for many years. I have observed that where the air is humid, there is plenty of water on and in the ground. It just needs to be filtered. We use a Reverse Osmosis filter here in China. In arid areas, there is damn little humidity, and only tiny amounts of water can be extracted from the air. It's not a real solution in the real world.
guzmanchinky
I would love to see this kind of technology replace the energy heavy desalinization.