The device could eventually provide households with all the drinkable water they need, by extracting dampness from the surrounding atmosphere. They are hoping that a version of this technology could probably start the supply of purified drinking water in the dry and poor areas of the world. To address this problem, researchers from UC Berkeley and MIT have created a solar-powered device that can be used in places like the desert to harvest water from a relatively untapped resource: air, which contains an estimated 13,000 trillion liters of water. MOF powders are porous, so they soak up water like a sponge - and not just liquid water. And there are very expensive ways of removing moisture from drier air. "I call it personalized water". Future versions of the water harvester could use better MOF materials that can collect more water, or the design could be improved to maximize efficiency. The material can also be tweaked to be more effective at higher or lower humidity levels.
Yaghi is the inventor of the metal-organic framework (MOF), a tiny grid made of aluminum or magnesium mixed with organic molecules. Currently, their MOF can only absorb 20% of its weight in water. In the last 20 years, researchers have created over 20,000 different MOFs for a wide variety of applications, such as separating methane and water from other gasses.
Another researcher, Li Kang, Professor of Chemical Engineering at Imperial College, London pointed out in an email to Gizmodo that this research wasn't adding much new in terms of our knowledge of MOFs-but that doesn't mean it's not exciting. The MOF used in the new device is optimized specifically to capture water in low humidity conditions.
An illustration of the structure of MOF-801, a MOF design that's been optimized specifically to capture water at low relative humidity. The MOF particles capture water vapor from the air, and the thermal energy from the sun drives the water out of the MOF cage and onto the condenser, from which it drips into a container. Run continuously, it "pulls" 2.8l of water out of desert air per 24-hour cycle.
Scientists at the MIT technology lab have been working together with the University of California, Berkeley to create this solar-powered harvester. "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".
Researchers tuned the chemical composition of a MOF to be hydrophilic, which in a powder form cannot only suck up liquid water but also absorb water vapour.
Yaghi talks about his work in the video below. The harvester uses sunlight to heat the MOF, driving off the water vapor and condensing it for use.
"That is something one could collect in less than an hour with this system", Yaghi points out. This is a major breakthrough in water harvesting technology, as most of the other available methods are either power hungry (like water dehumidifier) or not this efficient (fine fog-nets). Such a device would probably be about the size of a suitcase, she noted. But this practice is usually done in coastal regions where there is a humid environment.
But MOFs can also be optimized for different sorts of conditions, Yaghi pointed out. This particular device is said to be able to produce close to 3 liters of water in a single day, which is more than enough to sustain a human being even in a desert.