Engineers at Lockheed-Martin recently developed and patented a molecular filtration membrane called Perforene which can desalinate seawater using only 1/100th the energy of the best existing desalination systems.
Perforene is made from graphene, the exciting new nanomaterial which comes in the form of one-atom thick sheets of carbon atoms. Like an overzealous nanotechnology, graphene seems to photobomb itself in as the solution to numerous environmental problems such as, storing electricity, removing air pollution, advanced photovoltaics, high strength materials and now desalinating water.
Under a microscope, this material looks like a mesh net with holes as small as one hundred nanometer. These holes are small enough to block the chlorine and sodium ions in salt water but large enough to allow pure water molecules to pass through.
The material was invented by Lockheed engineer. In an interview with Reuters, Stetson said that this new material is 1000 times stronger than steel and 500 times thinner than the best existing reverse osmosis desalination filter.
He said, “The energy that’s required and the pressure that’s required to filter salt is approximately 100 times less.”
Why desalinating water is not energy efficient
Desalination typically uses at least 3 kilowatt-hours per cubic meter. To put this into familiar terms, filling a 2 liter bottle with desalinated water consumes the same amount of energy as running a 15-watt compact fluorescent light for 24 minutes.
The energy required to purify two liters of freshwater would only run the same light for less than two minutes.
This may not seem like a lot of energy, but it adds up.
According to information published by the International Renewable Energy Agency (IRENA), the world’s desalination plants consume approximately 360 million kilowatt-hours each day. Because of their gluttonous energy consumption, desalination plants are nearly always collocated with electrical power generating stations.
Nuclear power is often used. But in a bit of political doublespeak, the desalination plants are said to generate electricity. Electricity “generated” by existing desalination plants is only the excess energy produced by the collocated power plant that hasn’t been consumed.
If unconsumed energy is the same things as producing energy, Lockheed-Martin’s desalination technology might become one of the most important sources of energy and water in the Middle East. The company is seeking commercialization partners and hopes begin manufacturing this amazing new material in 2015.
Image of graphene molecular sheet via shutterstock