Luke Skywalker and his fellow moisture farmers on Tatooine would be proud.
Researchers from the Massachusetts Institute of Technology built the solar-powered harvester using a metal–organic framework (MOF), a material invented in the 1990s by study senior author Omar Yaghi, senior faculty scientist at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and a professor of chemistry at UC Berkeley.
MOFs combine metals with organic molecules, or ligands, to form rigid, porous structures that can store gases and liquids. Yaghi and his research team synthesized a large-pore MOF made of zirconium metal and adipic acid to bind water vapor. While the material has a high affinity for water molecules, it easily releases the concentrated water with a slight change in temperature.
They published a proof-of-concept paper in 2014, but to demonstrate this in a real-world environment, he teamed up with Evelyn Wang, a mechanical engineer at MIT.
Using 1 kilogram of the MOF, they created a solar-powered prototype that is capable of generating 2.8 liters of water from ambient air after 12 hours. The humidity during that period ranged from 20-30 percent, conditions as arid as a desert.
“This is a major breakthrough in the long-standing challenge of harvesting water from the air at low humidity, and it’s also a significant step towards commercialization,” said Yaghi. “Current dehumidifiers are powered by electricity, so creating that extra water ends up costing extra energy. My vision for the future direction of this technology is to have water off-grid, where you have a ‘personalized water device’ at home running on ambient sunlight for delivering water that satisfies the needs of a household.”