Researchers build prototype device capable of pulling water from the air

Researchers build prototype device capable of pulling water from the air

A team of researchers from MIT and UC Berkeley have built a prototype solar-powered device that can pull or extract fresh water from the air.

The “personalized water” harvester is a small, solar-powered device that requires just 20 to 30 per cent humidity to work. Prof. Omar Yaghi, one of the scientists involved in the project, envisions a future where such devices would make it possible for water to be supplied off-grid.

Envisioning the future, Yaghi said, “Water is supplied off-grid, where you have a device at home running on ambient solar for delivering water that satisfies the needs of a household.”

Yaghi, a professor of chemistry at UC Berkeley, and his team created a metal-organic framework (MOF) by blending metals with organic molecules. Then, he approached MIT’s mechanical engineer Evelyn Wang to know if the device could be used to create a water-collecting device.

Wang and her students successfully produced 3 quarts of water using 2.2 pounds of MOF over a period of 12 hours. It is a passive device, requiring no other source of energy than the sunlight.

The researchers expressed hope that members of the public will have one of these solar-powered devices installed on their roofs till rain comes again.

The research team informed that their harvesting device can collect nearly 2.8 liters of water per kilogram of porous metal-organic framework (MOF) at low humidity level of 20 percent. MOFs are compounds created by combination of organic molecules and specific metals. Researchers have created nearly 20,000 different MOFs using different organic molecules and metals. MOFs find applications in many fields of science and have been helpful in carrying out innovative projects.

For the current project, UC Berkeley and MIT researchers created a specific MOF that binds to water. The research team created a water collecting device using this MOF. Mechanical engineer Evelyn Wang of MIT and his students have worked hard on creating water harvester that runs on solar power. It is quite difficult to collect water in case of dry air (with humidity of less than 40 percent) and the device created by researchers works well in 20-30 percent humidity as well.

There are other compounds that can suck water from the air, zeolites for example, but Wang says it takes a significant amount of energy to get these materials to release the water.

Wang and her colleagues tested the prototype of their MOF-based device on the roof of a building at MIT, and it worked great.

Nearly 4 billion people across the world face acute water scarcity for at least once in a month. Water scarcity problem is even worse in some developing countries with hot climate. Such devices that require no energy source, can be very effective in dealing with water scarcity.

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