Inspiration struck Yi Zheng on a summer visit to a local dairy farm. There were cows and horses and, Zheng noticed, that meant that there was manure everywhere. An associate professor of mechanical and industrial engineering at Northeastern, Zheng is always looking around for ideas of how to create something functional out of natural materials. He wasn’t sure just yet what useful item he might be able to make from manure, but Zheng was pretty sure that that material held promise. And there would be no shortage of it.
When Zheng took the stinky bucket back to his laboratory, he and his team decided to heat it up to 1,700 degrees Celsius (3,092 degrees Fahrenheit) in order to kill off any bacteria in the manure. Once they’d done that, the researchers found that they had produced a powdered form of carbon. They used that black powder to make a foam, which they turned into a highly absorbent material that floats on the surface of water. When put in sunlight, the water beneath the black material would turn to steam and pass through it.
Manure isn’t the only natural material Zheng and his team use to desalinate seawater in sunlight. Other materials they have used to make a solar energy-triggered carbon filter have included tree leaves, cuttlefish ink, crab and lobster shells, hornet nests, and office paper waste. Their approach is described in a series of recent publications in the journals Cell Reports Physical Science, ACS Applied Materials & Interfaces, ACS Omega, Nanoscale and the Journal of Materials Chemistry A. ”The materials we use are totally natural, sustainable,” Zheng says. ”This natural material performs well, and is low-cost, easy to obtain, and easy to manufacture.”
Source: Phys.org
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