AUSTIN (KXAN) — Researchers with the University of Texas at Austin have developed a material capable of pulling water from the air, which can then be used for farming or drinking. The material is a thin film polymer that turns into a gel as it absorbs water, and then reverts back to a polymer once the water has been released. The work was published earlier this month in the science journal Nature Communications.
Youhong “Nancy” Guo, the lead author on the paper and a former doctoral student at UT, said the team was inspired by items found in the kitchen. These items, like flour, salt and sugar, usually become a “chunk” after being left outside, Guo said, which means they’re likely to absorb the water in the air.
Guo’s team used common ingredients, including konjac gum which is used for dieting, to create the polymer. This gum is able to attract water. The team mixes the ingredients together into a liquid before freeze-drying it. The assembly process takes only a few minutes.
“It can be used many times … without degradation of performance,” Guo said.
How does the water-absorbing film work?
Guo explained the gum in the film attracts water vapor from the air. At this point, the film turns into a gel. Once heated to around 110 degrees Fahrenheit, what’s called a hydrophobic reaction takes place.
The gel releases water vapor into the air. It can then be collected and cooled into liquid water. At this point, the gel reverts back to its original film state. The process can then be repeated. “We can do multiple cycles, like 15-to-24 cycles per day,” Guo said.
The film is capable of attracting water when the humidity is above 15%. Because the film starts as a liquid before it is freeze-dried, Nancy said it can be any size or shape a person needs.
The project was originally funded by DARPA, the Defense Advanced Research Projects Agency, for soldiers working in the desert.
A single pound of the material costs $2, Guo said. It can produce between one to two gallons of water per cycle, or more than 40 gallons of water a day.
Is the collected water safe to drink?
Guo said water collected using this method will likely need to be boiled before it is consumed, as the process also collects bacteria in the air. However, she said it is safe for agriculture.
“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 at the University of Texas, in a press release sent by 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.”
Water scarcity is becoming more of an issue in the last few decades. Nearly half of the land on Earth, 41.3%, is considered dryland, according to the United Nations, with 44% of the world’s farming occurring these areas.
The World Wildlife Fund reports 2.7 billion people around the world have issues locating water at least once a month. One-point-one billion people do not have easy access to fresh water.
This issue is growing thanks to climate change. Droughts are becoming more frequent and more extreme. According to the Environmental Protection Agency, average rainfall in Texas is expected to fall. Since the 1950s, aquifers in the state have seen water levels cut in half.
The University of Texas research team plans to optimize the material and find better ways to convert the water vapor into liquid.