Getting water to drought-stricken areas is an increasing concern for scientists. In the future, desalination systems will become simpler and more accessible to get water to those who need it, but another solution could be to just pull water right out of the air.
Engineers from the University of Texas in Austin have developed a low-cost gel that absorbs water from the air of even very arid climates.
Giving anyone anywhere access to water
Desalination systems can be difficult to maintain, and they necessitate the presence of a body of water. This new gel not only pulls water straight from the air but is also made from very common materials. The team made it out of renewable cellulose and gum from konjac, a kind of root vegetable, that provides a hydrophilic (water-attracting) structure. To release water from the gel, the researchers added thermo-responsive cellulose which becomes hydrophobic (water repellant) when heated. It doesn’t need so much heat, though, that the water evaporates in the process.
These materials only cost about two dollars per 2.2 pounds, and this amount is enough to absorb 1.5 gallons of water a day in areas of 15 percent humidity. With more humidity, even more, water is absorbed, with 30 percent humidity yielding 3.4 gallons a day.
“This new work is about practical solutions that people can use to get water in the hottest, driest places on Earth,” says Guihua Yu, professor of materials science and mechanical engineering in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering at the University of Texas at Austin. “This could allow millions of people without consistent access to drinking water to have simple, water generating devices at home that they can easily operate.”
Other methods of pulling water from humid air are typically energy-intensive and don’t absorb much water. This simple gel film can be scaled and improved to absorb more water with varying levels of thickness, and the team hopes people will be able to buy it at hardware stores or make it themselves.
This gel is flexible and making it only requires the premade mix which can be poured into a mold. “The gel takes two minutes to set simply. Then, it just needs to be freeze-dried, and it can be peeled off the mold and used immediately after that,” says Weixin Guan, a doctoral student on Yu’s team and a lead researcher of the work.
Source Study: Nature Communications — Scalable super hygroscopic polymer films for sustainable moisture harvesting in arid environments | Nature Communications