A changing climate is putting more pressure on the world’s supply of clean water. But an amphibian might have the answer.
A team of researchers at the University of Nevada, Las Vegas, has developed a material that harvests atmospheric water more efficiently than current technologies. And it’s all thanks to a frog.
Listen to the Deep Dive:
Frogs don’t consume food and water the way we do. Food is taken in orally, but the eyeballs fall inward to push it down the throat. Water, however, is absorbed through their skin.
It was this process that inspired a new ultra-absorbent material that came exclusively from studying hydrogels. The gels create a barrier that keeps out contaminants but allows water to pass through.
CAPTION: Jeremy Cho, assistant professor, Department of Mechanical Engineering“A hydrogel is a soft polymeric material that can swell with water, meaning it is very permeable to water, just like skins in organisms,” says Jeremy Cho, one of the researchers on the team.
A hydrogen membrane and a liquid desiccant was the winning combination that permits rapid capture and large quantity storage for freshwater distillation.
“We observed that it could capture water at incredibly fast rates. We captured two to six liters per day per square meter of membrane area in Las Vegas air — the driest city in the United States,” Cho says.
The liquid desiccant attracts water and absorbs water vapor from the air, even when the relative humidity is as low as 10 percent.
The most challenging obstacle was to filter outside air particulates and contaminants. A hydrogel membrane was added between the desiccant and the air.
It sounds like an easy solution, but finding the just-right hydrogel took two years of experimentation resulting in two published papers. “It took a lot of careful hydrogel synthesis and experimentation to verify our theory,” he tells KUST Review.
| What’s new?
Though atmospheric water harvesting processes have been around for a long time, often repackaging old technologies, the team’s method is based on new tech.
“Our work is different in that we are not creating a new sorbent to be cycled, or relying on an old tech developed for a different application. We are presenting a new membrane-based method where water can be continuously captured into a liquid desiccant and released (distilled) in another location.
The segregation of processes is what’s key here as it allows you to separately optimize and control each process for better overall performance and efficiency. It gives us flexibility in how we can design a complete water-harvesting system. If we want to be solar or waste-heat or electrically powered, we can build different systems that still rely on the same membrane-based capture approach developed because of this flexibility,” Cho says.
| It’s not just for drinking
The majority of the market is focused on drinking water, which is only a fragment of overall water consumption, so the team initiated a start-up company with hopes its tech has a massive impact on sustainability and water sourcing.
Cho adds, “This approach was invented with water-stressed arid regions in mind, and sustainability has been part of the vision from the very beginning.”
This includes considering the current level of water stress and how their tech can impact water usage, conservation and regulation. Regulators are consistently looking toward lower consumption and water reclamation, and companies that look to environmental, social and governance factors when making investment calls are seeking to be water-neutral or water-positive.
Regulators in Nevada sometimes try to put off businesses from setting up there, based on their water-consumption forecasting. Cho and his team are hoping to eliminate this market barrier, enhancing the local economy.
| At what cost?
The problem is that these water solutions are more costly than tap water, but Cho says his team’s goal is to ensure their start-up company, WAVR Technologies, is focused on developing solutions to supply water to make up for these consumptive losses.
| Who is willing to pay the price?
Cho says there are many industries in Las Vegas looking for solutions, including real estate, hospitality, construction and high-tech manufacturing. “We’ve been talking to them, they’re all looking for a solution and are willing to pay for it. And from what we can tell right now, the amount they’re willing to pay seems to be achievable from a technoeconomic standpoint when we scale up our technology.”
“Climate change is real, and whether or not you accept the science that we are causing it, you are paying for it. In arid regions, it is extremely visible through our water resources, our utility bills, and our abilities to do business and live in our communities. We should be more responsible in how we use our water and do what we can to reclaim it. And whatever water we cannot reclaim, let’s consider sourcing that from the air—a hidden resource that surrounds us all,” Cho tells KUST Review.
The team at WAVR Technologies expects its first prototype to be ready by the end of 2025.
