University of Rochester researchers have built a solar-powered desalination device that doesn't leave behind brine — the concentrated saltwater that conventional plants dump back into the ocean, where it raises salinity and starves sea life of oxygen. The panels are black metal etched with femtosecond lasers, so the surface both absorbs nearly all sunlight and wicks a thin film of water across it, distilling fresh water and shunting the leftover salts to untreated edges instead of letting them clog the works.
To move the salt, the team borrowed a kitchen annoyance. "If you drop coffee on a surface, eventually the water evaporates, and there's a ring left at the outer edge that is the concentrated coffee particles," said optics professor Chunlei Guo. "We use that same principle to advance the salts to the passive region."
When tested on Pacific, Atlantic, and Indian Ocean waters, the surface remains self-cleaning and recovers nearly all the salt as solids. A related version, using the same panels seeded with hydrogen titanate nanoparticles, removed about half the lithium from Great Salt Lake samples.
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