Lockheed Martin, a defense contractor known for building jet fighters and lethal missiles, says it has found a way to slash the amount of energy needed to remove salt from seawater, potentially making it vastly cheaper to produce clean water at a time when scarcity has become a global security issue.



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.



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.



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.



Jeffrey Grossman, an associate professor at the Massachusetts Institute of Technology who has done research on graphene membranes for filtration, said he was not familiar with details of Lockheed's work. But he said finding a way to produce graphene sheets with nanometer-sized holes could produce a major advancement in desalination efficiency.



"If you can design a membrane that's completely different than what we use today, then there's a chance for more than two orders of magnitude (100 times) increase in the permeability of the membrane," Grossman said.



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.