A handheld device that can extract and convert water molecules from the air into drinkable water has been designed by researchers in California, USA.

The atmospheric water harvester uses only ambient sunlight as its energy source and is proven to work in extreme weather, according to scientists at the University of California, Berkeley.

An ultra-porous material known as a metal-organic framework (MOF) was used to extract water repeatedly in the hottest and driest place in North America - Death Valley National Park. These tests showed the device could provide clean water anywhere, addressing a critical need as climate change exacerbates drought across many parts of the world.

Berkeley chemistry professor Omar Yaghi, who invented MOFs and is leading the study, said, “The UN projects in the year 2050 that almost five billion people on our planet will experience some kind of water stress for a significant part of the year. This is quite relevant to harnessing a new source for water.”

Yaghi’s study says MOF-powered harvesters are powered entirely by sunlight and do not require additional power sources. They can operate at high capacity, in low-humidity conditions, while remaining energy efficient, making them a powerful tool to address water scarcity. This technology can also be used to secure pure water in regions where water is abundant but not clean, according to the study.

Yaghi, who is co-director of the university’s Bakar Institute of Digital Materials for the Planet (BIDMaP), said, “What we’re doing at BIDMaP is creating what I call the digital innovation cycle, to connect the molecule, the material, and how the material is configured and fits into the device, including the actual device design, its efficiency and performance.

“All of these are connected, and each part has to be optimised to get the highest performance.”

Yaghi and his research team tested the technology in Berkeley and Death Valley National Park in California. The device extracted water repeatedly in both locations, despite extremely low-humidity conditions and wide-ranging daily temperatures, producing 200 grammes of clean water per square metre of water vapour.

The team is now working to further develop the prototype, looking at efficiency, size and scale. Yaghi said he could see one day a widespread adoption of both household and community-scale water harvesters, adding, “It gives individuals water independence.”

The study from UC Berkeley College of Computing, Data Science & Society was originally published in the journal Nature Water.