Scientists and engineers at The University of Texas at Austin have developed a solution to assist those in areas without access clean drinking water and that have water shortages, particularly pulling water from desert air.
According to the university, "the team developed a low-cost gel film made of abundant materials that can pull water from the air in even the driest climates. The materials that facilitate this reaction cost a mere $2 per kilogram, and a single kilogram can produce more than 6 liters of water per day in areas with less than 15% relative humidity and 13 liters in areas with up to 30% relative humidity."
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.
The film can be molded and is flexible, requiring only the gel precursor to make it.
The research from this team follows previous research about pulling water out of the atmosphere and the ability to create self-watering soil, reported the university, which are designed for high-humidity environments.
“This new work is about practical solutions that people can use to get water in the hottest, driest places on Earth,” said Guihua Yu, professor of materials science and mechanical engineering in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering, reported the university. “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.”
Renewable cellulose and konjac gum (a main hydrophilic skeleton) were used, since the structure of gum speeds the moisture-capturing process, according to the team, reported the university. Additionally, the team used a thermo-responsive cellulose with hydrophobic interaction that when heated will release the collected water immediately.
This process creates an environment where the overall energy input to produce water is minimized, but the challenge is scaling the process up, according to the team, reported the university.
“This is not something you need an advanced degree to use,” said Youhong “Nancy” Guo, the lead author on the paper and a former doctoral student in Yu’s lab, now a postdoctoral researcher at the Massachusetts Institute of Technology, reported the university. “It’s straightforward enough that anyone can make it at home if they have the materials."
“The gel takes 2 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,” said Weixin Guan, a doctoral student on Yu’s team and a lead researcher of the work, reported the university.
Researchers add that "creating thicker films or absorbent beds or arrays with optimization could drastically increase the amount of water they yield."
The research was funded by the U.S. Department of Defense’s Defense Advanced Research Projects Agency (DARPA). According to the university, drinking water for soldiers in arid climates is a major component of the project.