Sun-powered gel is a speedy new water filter

Written by
Colton Poore, Andlinger Center for Energy and the Environment
Feb. 15, 2023

Reliable access to clean water remains a challenge for over two billion people across the globe. Now, Princeton researchers in Rodney Priestley’s lab have invented a low-cost way to make clean water widely available – and it only requires sunlight to work.

Users can simply toss a disc of the sponge-like gel into a water source until it becomes saturated, then remove it and place it in the sun. In as little as 10 minutes the filter can release over a gallon of clean water.

Unlike other solar water filters, it does not rely on evaporation and requires very little energy and time to produce the clean water. The gel is engineered to absorb or repel water based on its temperature and requires only heat from the sun to release the clean water.

The solar absorber gel works almost four times faster than an earlier version developed by the lab two years ago, and the researchers say it can produce enough clean water to meet daily needs in many parts of the world. Learn more about the technology in this video.

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