Researchers from MIT Massachusetts and the University of California (UC) Berkeley have created a device that can pull fresh water out of thin air by just using the light of the Sun. According to researchers, this device, dubbed solar power harvester, is made of a unique material called metal-organic framework (MOF) and can work even in places where humidity levels are as low as 20 percent. Researchers say the device needs only sunlight to function efficiently and generate water out of the air.

Solar-power harvester can help fight water scarcity problem

Presently, over 60 percent of the population worldwide (nearly 4 billion people) is experiencing a shortage of clean water. At the same time, scientists estimate that the all the air around us worldwide contains approximately 13,000 trillion liters of water. The researcher who created the new solar-power harvester believes this device could be of great help to some of the driest regions on Earth where water scarcity is a big problem and where people don’t have clean enough, fresh water to drink.

Solar-power harvester is currently in prototype phase, according to its inventors, although the results obtained during initial trials have been pretty encouraging.

Scientists have tested the prototype device under conditions of 20 to 30 percent humidity. Using 1 kilogram of MOF and operating the device for 12 hours, they were able to get about 2.8 liters of clean water from the air. The team, led by Evelyn Wang (from MIT) and Omar Yaghi (UC), even carried out the trial on the rooftop at MIT to demonstrate that this device can work in real-world conditions.

What is a metal-organic framework (MOF)?

MOF are a particular type of materials in which organic molecules are combined with metals like aluminum or magnesium in a specific arrangement to make porous, rigid, structures that can store liquids or gasses. To the naked eyes, MOFs appear no different than sand particles. Over 20,000 different types of MOFs have already been created by researchers in the past two decades, and many of the structures are being used in a variety of applications such as capturing carbon dioxide, storing chemicals like methane or hydrogen, etc.

The MOF used in solar-powered harvester was first created in 2014. It is based on adipic acid and zirconium that give it abilities to bind water vapors. These MOF crystals are compressed between a condenser plate and a solar absorber. When air passes through the MOF material, it traps water in nanometer-sized pores. This trapped water, when heated by ambient sunlight, is released from the pore and gets condensed eventually.

Omar Yaghi, the UC Berkeley researcher who developed the first MOF about 20 years ago, considers this device a huge success in generating water from the low-humidity air. Yaghi says their device can help achieve the vision of the future where people would be able to generate “personalized water” for their households without any need for a water grid.

She says the prototype device is just a demonstration of the concept, and there is much room for improvement to double the amount of water collected. The team is planning to create a 30-liter system that would provide safe, drinking water for a family of four each day.

The detailed results of this research have been published in Science magazine.