Solar-powered sponge technology could save Texas water

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The solar-powered filtration device uses sunlight and a chemically-altered sponge (enlarged on right) to rid water of harmful toxins.

Photo Credit: Donglei Fan and Weigu Li | Daily Texan Staff

A solar-powered sponge technology may be part of the solution for water scarcity. Researcher Donglei Fan and her team set out to solve this problem with solar steaming, a process that filters water with a sponge, at low cost and low energy.

Solar steaming uses the sun — rather than other energy sources that may be nonrenewable — to heat water, remove contaminants and yield purified water, Fan said. This more sustainable water-purification technology reduces contaminants in river water such as heavy metals and infections which can cause permanent nerve damage.

“Take for example, water from the Colorado River,” Fan said. “Before filtering, it shows signals of bacteria, and people can’t consume it. After using our device, the water becomes drinkable. It holds up to the extremely stringent standards of the Environmental Protection Agency for water safe for consumption.”

Chemically altered beads of an organic compound are spread out on the surface of a 3D sponge, which absorbs water quickly in comparison to other sponges, according to Fan. She added that this gives the sponge high evaporation rates and allows the sponge to also serve as a freestanding water reservoir.

The device reached energy efficiency levels of 88 percent, she added.

“This 3D sponge material is completely new, and its performance is among the highest out there,” Fan said. “It’s really good at removing mercury, which was an important concern for us. We are also one of the first teams to have a collection method for our water, which is in the sponge.”

The resources to create this purification system are also cheap, Fan said. The research is aimed at addressing the practical concerns of water scarcity and something that costs little money and energy could be useful to families in the future, she added.

“Traditional water resources may not be efficient in supplying the need of water,” Fan said. “This solar-driven technology means people would be able to directly filter their water. Every home can have a nice scaled device to supply needs of family.”

Fan said this method reduces the stress on the environment to provide drinkable water, a critical issue in Texas, where high temperatures create more demand for water. The population increases in Texas, notably Austin, also add to the need for water technologies, she added.

“When population increases like this, water is among one of the first problems,” Fan said. “Texas is so hot that, even now, we have a shortage of water in the summertime … this work is using the sun to create expandable technology for the future.”