MIT/Berkeley’s water-harvesting device uses porous metal-organic frameworks and sunlight to transform air into water at a rate of about 3-liters a day. (Image credit MIT)
It’s all in the MOFs- transforming air into water isn’t some kind of alchemic wizardry, nor is it done with tech from the future but rather it’s an ingenious solution using compounds of metal clusters and organic ligands. Yep, that’s the wonders of chemistry or rather the magic of “metal-organic frameworks” (MOFs), which researchers from MIT and Berkeley harnessed to develop a device that transforms air into water.
The technology would be a great solution for those living in arid or desert climates where water is scarce or nonexistent, or perhaps as a survival aid in situations where potted water is unavailable. Whatever the case may be, the device doesn’t require a power source or the inclusion of a freezer to harvest water but only needs air and sunlight, something most arid climates have in abundance.
Let me break it down for you regarding the mechanics of how it works- housed inside of an acrylic box is the metal-organic framework material, which is porous like a sponge and has hydrophilic, water attracting properties. The top of the box is painted black and heats the air inside at the top of the box while the air at the bottom retains the same temperature as the outside area around it. The air trapped in the MOF is released as a vapor due to the temperature differential and transformed into water as it cools and collects at the bottom of the cube, in much the same fashion as modern CPU heatsinks work.
Tests have shown that just over two pounds of the material could produce as much as three liters of water every twelve hours in a climate with 20% humidity or enough for one person to live on per day. All that’s needed is for users to simply open the box, collect the water and let fresh air in- wash, rinse, repeat. Live in a climate with more or less humidity? No problem, the MOFs can be ‘tuned’ to function with the relative humidity by combining different metals with different compounds to achieve optimal results.
“By carefully designing this material, we can have surface properties that can absorb water very efficiently at 50 percent humidity, but with a different design, it can work at 30 percent,” stated MIT grad student Hyunho Kim who is part of the development team behind the device. He goes on to say, “By selecting the right materials, we can make it suitable for different conditions. Eventually, we can harvest water from the entire spectrum.”
Of course, the researchers are still working to refine their MOF design as it currently can only collect about 25% of its own weight in water but they hope to up that percentage by 50% for arid climates in the near future.
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