Water Harvester Pulls Drinkable Water from Dry Air

Water Harvested in the Mojave Desert
UC Berkeley postdoctoral fellow Mathieu Prévot displays water collected by the harvester (foreground) in the Mojave Desert.

Water from thin air? It sounds like something from a sci-fi novel, but researchers from the University of California, Berkeley are actually making it happen. The scientists have invented a powdery substance, metal-organic framework (MOF), that literally turns low humidity air into drinkable water. This water harvester can pull over 5 cups of water from low humidity air per day per 2.2 pounds of water absorbing materials.

The water harvest is capable of creating enough water to enable individuals to survive in extreme arid conditions, even with water to spare.

“What it does is collect water from the atmosphere to very dry conditions and then releases it so we can harvest it as liquid water,” says Eugene Kapustin, a Ph.D. student at UC Berkeley.

The device functions much as a sponge, according to Kapustin. The metal organic framework is a “pile of powder full of organic molecules and metals. The mixture is left out overnight so water molecules in the environment can attach to the metal-organic framework. To extract the water, the mixture is placed in a water-tight tank and warmed with heat lamps. Droplets of water cling to the sides and then subsequently collected as pure H2O.”

Water scarcity is a hot topic, especially in arid regions such as California. Researchers report that they will soon produce a microwave sized water harvester that could pull a day’s worth of water from the air – even in low humidity air in a desert.

The start-up company for this project, Water Harvester, Inc. hopes to have water harvesters available soon. Devices that will be marketed include an oven sized device that can produce 7-10 litres of water per day. That is enough drinking and cooking water for 2-3 adults for a day. Another version, about the size of a small refrigerator, can produce up to 200-250 litres of water per day, enough for an entire household to use for drinking, cooking and showers.

Water Harvester Team
UC Berkeley graduate student Nikita Hanikel, Grant Glover of the University of South Alabama and UC Berkeley postdoc Mathieu Prévot display the water collected from the water harvester last fall in the Mojave Desert.

The company’s ultimate goal is to create large systems to harvest water for entire villages. The researchers hope to produce a harvester that can produce 20,000 litres of pure water per day, enough to provide water for an entire village. The devices will be powered through solar energy, making the entire process green.

Water scarcity is a looming threat to countries around the world. Omar Yaghi, principal researcher and UC Berkeley professor of chemistry, stresses the importance of making water available for all people.

“This water mobility is not only critical to those suffering from water stress, but also makes possible the larger objective—that water should be a human right,”

[source: Rapid Cycling and Exceptional Yield in a Metal-Organic Framework Water Harvester]

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