The process, officials and engineers at Lockheed Martin Corp say, would enable filter manufacturers to produce thin carbon membranes with regular holes about a nanometer in size that are large enough to allow water to pass through but small enough to block the molecules of salt in seawater. A nanometer is a billionth of a meter.
Because the sheets of pure carbon known as graphene are so thin - just one atom in thickness - it takes much less energy to push the seawater through the filter with the force required to separate the salt from the water, they said.
The development could spare underdeveloped countries from having to build exotic, expensive pumping stations needed in plants that use a desalination process called reverse osmosis.
"It's 500 times thinner than the best filter on the market today and a thousand times stronger," said John Stetson, the engineer who has been working on the idea. "The energy that's required and the pressure that's required to filter salt is approximately 100 times less." (...)
Stetson, who began working on the issue in 2007, said if the new filter material, known as Perforene, was compared to the thickness of a piece of paper, the nearest comparable filter for extracting salt from seawater would be the thickness of three reams of paper - more than half a foot thick.
"It looks like chicken wire under a microscope, if you could get an electron microscope picture of it," he said. "It's all little carbon atoms tied together in a diaphanous, smooth film that's beautiful and continuous. But it's one atom thick and it's a thousand time stronger than steel."
by David Alexander, Reuters | Read more:
h/t and image via: 3 Quarks Daily
