Inexpensive gel extracts drinking water from the dry desert air

More than a a third of the world’s population lives in arid areas, areas experiencing significant water shortages. Engineers and scientists from the University of Texas at Austin have developed a unique solution that can help people in these areas get clean drinking water.

Researchers have developed an inexpensive gel film consisting of a large number of materials that can draw water out of the air even in the driest climates. The materials that contribute to this reaction cost only $ 2 per kilogram, and one kilogram can produce more than 6 liters (~ 1.6 gallons) of water per day in areas with relative humidity less than 15% and 13 liters (~ 3.4). gallons) in areas with relative humidity. with relative humidity up to 30%.

The study draws on previous research group breakthroughs, including the ability to draw water from the atmosphere and the application of this technology create self-watering soil. However, these technologies have been developed for conditions with relatively high humidity.

“This new work is about practical solutions that people can use to get water in the hottest and driest places on Earth,” said Guihua Yu, a professor of materials science and mechanical engineering at the Walker Department of Mechanical Engineering at Cochrell School of Engineering. “It could allow millions of people who don’t have constant access to drinking water to have simple water-producing devices at home that they can easily manage.”

The new work was published in the journal on May 19, 2022 The nature of communication.

The researchers used renewable cellulose and a common kitchen ingredient, cognac gum, as the main hydrophilic (attracted to water) skeleton. The structure of gums with open pores accelerates the moisture process. Another developed component, thermoreactive cellulose with hydrophobic (water-resistant) interaction when heated, helps to immediately release the collected water, so that the total energy consumption for water production is minimized.

Other attempts to draw water from desert air are usually energy-intensive and do not produce much. And while 6 liters doesn’t sound like much, researchers say creating thicker films or absorbent beds or arrays with optimization can dramatically increase the amount of water they provide.

The reaction itself, according to researchers, is simple, which reduces the problem of increasing its scale and achieving mass use.

“It’s not something you need a degree to use,” said Yuhon “Nancy” Guo, lead author and former doctoral student at the Yu Laboratory and now a graduate student at the Massachusetts Institute of Technology. “It’s simple enough that anyone can do it at home if they have the materials.”

The film is flexible and can be formed into different shapes and sizes, depending on the needs of the user. For the manufacture of the film requires only a precursor of the gel, which includes all the relevant ingredients poured into the mold.

“The gel just hardens in 2 minutes. Then you just need to freeze it, then take it out of the mold and use it right away, ”said Weixin Guan, a doctoral student at the Yu team and a leading labor researcher.

Reference: “Scalable superhygroscopic polymer films for sustainable moisture collection in arid conditions” Yuhon Guo, Weixin Guan, Chusin Lei, Heny Lu, Wen Shi and Guihua Yu, May 19, 2022, The nature of communication.
DOI: 10.1038 / s41467-022-30505-2

The study was funded by the US Department of Defense’s Advanced Research Projects Agency ([{” attribute=””>DARPA), and drinking water for soldiers in arid climates is a big part of the project. However, the researchers also envision this as something that people could someday buy at a hardware store and use in their homes because of its simplicity.

Yu directed the project. Guo and Guan co-led experimental efforts on synthesis, characterization of the samples, and device demonstration. Other team members are Chuxin Lei, Hengyi Lu, and Wen Shi.