An inexpensive solar water filter removes lead and hydrocarbons

 An inexpensive solar water filter removes lead and hydrocarbons?

A new invention that uses sunlight for water purification could help solve the problem of providing clean water outside the mains.

The device resembles a large sponge that absorbs water but leaves behind contaminants, such as lead, hydrocarbons, and pathogens. To collect the purified water from the sponge, it is simply placed in the sunlight. Princeton researchers described the device in an article published in the journal Advanced Materials.

Inspiration for the device came from puffer fish, a species that takes in water to swell its body when threatened, and then releases water when danger passes, said the device's co-inventor Rodney Priestley, professor of Chemistry, Biological Engineering. and vice dean of innovation at Princeton.

"For me, the most exciting thing about this job is that it can operate completely outside of the supply networks, both large and small," Priestley said in a statement. "It could also work in the developed world where low-cost, non-powered water purification is needed."

Xiaohui Xu, a Princeton Presidential Postdoctoral Research Fellow in the Department of Chemical and Biological Engineering and a co-inventor, helped develop the gel material at the heart of the device.

"Sunlight is free," Xu said, "and the materials to make this device are inexpensive and non-toxic, so this is a cost-effective and environmentally friendly way to generate pure water."


The authors noted that the technology offers the highest passive solar water purification rate of all competing technologies.


One way to use the gel would be to place it in a water fountain at night and place it in sunlight the next day to generate the drinking water of the day, Xu said.

The gel can purify water contaminated with petroleum and other oils, heavy metals like lead, small molecules, and pathogens like yeast. The team demonstrated that the gel maintains its ability to filter water for at least ten soak and discharge cycles without a detectable reduction in performance. The results suggest that the gel can be used repeatedly.