Low cost gel film can extract drinking water from the desert air

More than a third of the world’s population lives in arid areas, areas that experience significant water shortages. Scientists and engineers from the University of Texas at Austin have developed a solution that could help people in these areas access safe drinking water.

The team developed a low-cost gel film made from abundant materials that can draw water from the air in even the driest climates. Materials that facilitate this reaction cost only $2 per kilogram, and a single kilogram can produce more than 6 liters of water per day in areas with relative humidity below 15% and 13 liters in areas with high humidity. relative humidity can reach 30%.

The research builds on the team’s previous breakthroughs, including the ability to extract water from the atmosphere and applying this technology to create self-watering soil. However, these technologies were designed for relatively humid environments.

“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 mechanical engineering department of the Cockrell School of Engineering. “It could enable millions of people without constant access to clean water to have simple water-generating devices at home that they can easily operate.”

The new paper appears in Nature Communication.

The researchers used renewable cellulose and a common kitchen ingredient, konjac gum, as the primary hydrophilic (water-attracted) skeleton. The rubber’s open-pore structure speeds up the moisture-locking process. Another engineered component, heat-sensitive cellulose with hydrophobic (water-resistant) interaction when heated, helps release collected water immediately so that the overall energy input to produce water is minimized.

Other attempts to extract water from the desert air are usually energy-intensive and do not produce much. And while 6 liters might not seem like a lot, the researchers say that creating thicker films or optimized absorbent beds or networks could significantly increase the amount of water they produce.

The reaction itself is simple, the researchers said, reducing the challenges of scaling it up and using it on a massive scale.

“It’s not something you need an advanced degree to use,” said Youhong “Nancy” Guo, the paper’s lead author and a former doctoral student in Yu’s lab, now a postdoctoral researcher. at Massachusetts Institute of Technology. “It’s simple enough that anyone can make it at home if they have the materials.”

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

“The gel takes 2 minutes to just set. Then you just need to freeze-dry it, and it can be peeled off the mold and used immediately after that,” said Weixin Guan, a doctoral student in Yu’s team and principal investigator. work. The researchers envision this as something people might one day buy at a hardware store and use at home because of the simplicity.