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."
Access to clean drinking water is increasingly seen as a major global security issue. Competition for water is likely to lead to instability and potential state failure in countries important to the United States, according to a U.S. intelligence community report last year. . .
Lockheed still faces a number of challenges in moving to production of filters made of graphene, a substance similar to the lead in pencils. Working with the thin material without tearing it is difficult, as is ramping up production to the size and scale needed. Engineers are still refining the process for making the holes. . . .
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."
Thickness is one of the main factors that determines how much energy has to be used to force saltwater through a filter in the reverse osmosis process used for desalination today.
"The amount of work it takes to squeeze that water through the torturous path of today's best membranes is gone for Perforene," Stetson said. "It just literally pops right through because the membrane is thinner than the atoms it's filtering."
Notaro said Lockheed expects to have a prototype by the end of the year for a filter that could be used as a drop-in replacement for filters now used in reverse osmosis plants. The company is looking for partners in the filter manufacturing arena to help it commercialize Perforene as a filter in the 2014-2015 time frame, he said.
Lockheed officials see other applications for Perforene as well, from dialysis in healthcare to cleaning chemicals from the water used in hydraulic fracturing, or "fracking," of oil and gas wells.
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David Alexander, "Pentagon weapons-maker finds method for cheap, clean water," Reuters, March 13, 2013.
At Via Meadia, Walter Russell Mead sees Lockheed Martin as throwing dirt on Malthus's grave:
Human life is always threatened by challenges, upheavals, and limitations, and there will always pessimists who claim that human race is doomed to defeat at the hands of these forces. Famously, in the 19th century, Thomas Malthus sounded dire warnings about the widespread suffering and chaos that will follow from our imminent overpopulation and two centuries later his contemporary followers are still singing the same tune.
But over and over again throughout the course of human history our ingenuity has been able to meet and overcome the challenges nature puts in our path. We have continually found new ways to make human life richer and more prosperous for more people in more places. The Lockheed filter still faces some obstacles in moving to mass production. It could wind up taking several years to reach the market, or could even totally fiz out. But either way, it represents the kind of creative ideas that are the real wealth of the human race.