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Clean water—Sunny desalination

A new method developed at Oak Ridge National Laboratory improves the energy efficiency of a desalination process known as solar-thermal evaporation. Scientists fashioned tubular devices using nanoengineered graphite foam coated with carbon nanoparticles and a superhydrophobic material that increased the absorption of light energy directly from the sun. The thermal energy was used to heat seawater, producing freshwater vapor that was fed into a condenser to make potable water. The system removed more than 99.5% of salt in simulated seawater and reached 64% solar-thermal conversion efficiency. “Using this improved solar-absorbing material for interfacial water evaporation represents a more efficient use of solar energy,” said ORNL’s Gyoung Jang. The experiment is detailed in the journal Global Challenges. The method can be scaled up into modular systems to provide clean water at remote locations or to serve communities affected by hurricanes or floods.