Off-Grid Devices Draw Drinking Water from Dry Air
Billions of people lack access to clean water for all or part of the year or must travel far to gather it. Extracting water directly from the air would be an immeasurable boon for them. But existing technologies generally require high moisture and a lot of electricity, which is expensive and often unavailable. The problem is now becoming more tractable. Robust systems are being developed that rely on readily available energy from the sun, are scalable and can work even in arid regions—where a third of the world’s population lives, often in poverty.
Collaborators at the Massachusetts Institute of Technology and the University of California, Berkeley, have tested an approach that requires no electricity at all. The team intends for its technology to overcome a notable problem with most materials capable of absorbing water from the atmosphere (such as the zeolites in humidifiers): aside from needing high humidity, they give up the trapped water only when heated substantially, which takes energy.