Device draws drinking water from desert air

With water scarcity becoming an increasingly pressing global problem, a team of chemists has developed a device that can pull potable water from air—even in the Mojave Desert. At the heart of the microwave-sized machine, from the University of California, Berkeley’s Omar M. Yaghi and colleagues, is an aluminum-based metal-organic framework (MOF), known as MOF-303 (shown). Although MOF-based water harvesters aren’t new, the current device is capable of harvesting 10 times as much water as earlier versions of this device that used MOF-801 (ACS Cent. Sci. 2019, DOI: 10.1021/acscentsci.9b00745). That boost in yield comes from solar- or battery-powered fans that drive water off the MOF as well as from MOF-303’s ability to hold more water than MOF-801 and its adsorbing and desorbing kinetics. MOF-303 pulls in and releases water much faster than MOF-801. In an arid indoor environment with a relative humidity of 32%, the device can generate 1.3 L of water for each kilogram of MOF in 24 h. The group also took the device out to the Mojave Desert, where it could pull as much as 0.7 L of water for each kilogram of MOF in 24 h. Yaghi has a start-up company, Water Harvesting, which is developing a commercial device based on the technology.