Apr 07, 2021

Low-Cost Solar-Powered Water Filter Removes Contaminants

The device resembles a large sponge that soaks up water but leaves contaminants behind.

solar powered

A water filter that uses sunlight to drive water purification to provide clean water has been created.

According to EurerkaAlert!, the device resembles a large sponge that soaks up water but leaves contaminants behind. To collect the purified water from the sponge it is placed in the sunlight. 

According to the device's co-inventor Rodney Priestley, the Pomeroy and Betty Perry Smith professor of chemical and biological engineering, and Princeton's vice dean for innovation, the inspiration for the device came from the pufferfish. Pufferfish take in water to swell its body when threatened and then release water when danger passes. 

"To me, the most exciting thing about this work is it can operate completely off-grid, at both large and small scales," said Priestley, reported EurekaAlert! "It could also work in the developed world at sites where low-cost, non-powered water purification is needed."

Princeton Presidential Postdoctoral Research Fellow in the Department of Chemical and Biological Engineering and co-inventor, Xiaohui Xu, also helped develop the gel material, a vital component of the device. The authors note that the technology delivers the highest passive solar water purification rate of any competing technology, reported EurekaAlert!

At the heart of the device is the gel, which changes depending on temperature. The gel consists of a honeycomb-like structure that is highly porous. The gel can purify water contaminated with oils, heavy metals including lead, small molecules, and pathogens, according to the team. 

The team showed that the gel maintains its ability to filter water for at least ten cycles of soaking and discharge with no detectable reduction in performance and the results suggest that the gel can be used repeatedly, reported EurekaAlert!

Xu took the device to Lake Carnegie on the Princeton University campus to demonstrate the device, placing the gel into the cool water of the lake, which contains microorganisms that make it unsafe to drink, letting it soak up the lake water for an hour. When the sun warmed the gel, pure water trickled into the container over the next hour, reported EurekaAlert!

Sujit Datta, assistant professor of chemical and biological engineering, and Craig Arnold, the Susan Dod Brown professor of mechanical and aerospace engineering and director of the Princeton Institute for the Science and Technology of Materials, collaborated on the development of the technology as well.

According to EurekaAlera!, the team is exploring ways to make the technology widely available.

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