Some say future wars will be fought over water, and a billion people around the world are already struggling to find enough water to live. Now researchers from the National University of Singapore (NUS) are coming to the rescue.
The NUS team created a substance capable of extracting water from the air without any external power source.
An airgel to extract water from the air
There is so much water in the Earth's atmosphere that it fills nearly half a trillion Olympic swimming pools. But the simple atmosphere has long been overlooked as a source of drinking water. To extract water from this underutilized source, a team led by Professor I have Ghim Wei of the Department of Electrical and Computer Engineering of the NUS created a type of airgel, a solid material that weighs almost nothing.
Under a microscope it looks like a sponge, but it doesn't need to be squeezed to release the water it absorbs from the air. It also does not require a battery. In a humid environment, just one kilogram of airgel is capable of extracting 17 liters of water from the air per day.
Water from the air with an airgel: how does it work?
The trick is in the long, snake-like molecules, known as polymers, that form the airgel. The special long-chain polymer consists of a sophisticated chemical structure that can continuously switch between attracting water and repelling water.
This “smart” airgel extracts water from the air, condenses it into a liquid and releases the water. When it's sunny, the intelligent structure can further increase the water release by switching to a state of total water repulsion. And it is very effective at this. 95 percent of the water vapor that enters the airgel comes out as water. In laboratory tests, the airgel provided water continuously for months.
The researchers tested the water and found that it met World Health Organization standards for drinking water.
The first device that does not require power
Other scientists have previously devised ways to extract water from the air, but their designs had to be powered by sunlight or electricity and had moving parts that needed to be opened and closed. The NUS researchers published their creation in the journal Science Advances (“Self-contained atmospheric water infiltration MOF array” ). They are now looking for industrial partners to expand the device for domestic or industrial use. Perhaps it could even find a place in endurance sports or survival kits, for example. “Given that atmospheric water is continuously replenished by the global hydrological cycle, our invention offers a promising solution to achieve sustainable freshwater production under a variety of climatic conditions, at minimal energy cost,” said Prof. I have.
