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New Process For Nanoscale Filtration Holds Promise of Cheap, Clean Water
New submitter Spinnakker writes "Lockheed Martin, traditionally known for its development of military systems and aircraft, has developed a process for perforating graphene (carbon sheets only one atom thick) that could potentially reduce the energy required for desalination by two orders of magnitude. The process tailors the hole size to the molecules being separated. In the case of desalination, one would create holes in the graphene large enough to allow water to pass but small enough to block the salt molecules. The advantage to using graphene comes from how extremely thin the material is compared to traditional filters. The thinner the filter, the less energy is required to facilitate reverse osmosis."
I remember when this theoretical technology was proposed about a year ago, and figured it would be a decade before they could actually do it.
Cheap desalinization and filtration would mean an end to one of the biggest world health problems(safe drinking water), and could improve world-wide standards of living dramatically.
...how many holes?
Enough to fill the Albert Hall
“He’s not deformed, he’s just drunk!”
I thought part of the problem with current desalination techniques was that it removed all of the salts making us have to go back and re-add a bunch of phosphates and whatnot that are found in fresh water sources and are somewhat expected/required by our and plant's biological functions. That is, we were making the water too pure to be used without additional processing. This sounds like that taken the next level, so how much more efficient can it really be if the process requires even more post-processing to make it usable?
Considering that the theoretical minimal energy requirement for seawater desalination is approx. 0.75 kWh/m3 and current RO technology can be as low as 1.5 to 2 kWh/m3 (+ an other 2 kWh/m3 to pretreat the seawater) then I am really wondering how they will gain two orders of magnitude less energy? Can anybody enlighten us about that?
Very similar article [slashdot.org] was published half a year ago. Is there something new now?
It's gone from "A group of MIT researchers" to "Lockheed Martin", the latter of which could actually make it commercially available.
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We have been polluting the water ever since the industrial age began and draining the water supply at the same time. Aquifers are getting depleted, its going to become an expensive problem. It is good to see this technology finally come about . It should help us bring water to arid lands. They say that with global warming it isn't the heat that is going to affect the plant life but the lack of water supply. It is an expensive proposition however to lay thousands of miles of pipe. But perhaps it will become cheap enough to take and desalinate water and fill up major rivers so that natural distribution can be restored. It would take a lot of energy to do it but with the two orders of magnitude cheaper maybe it would be cost effective? I would also suggest that we stop polluting the water with all the plastics and use it to recycle. We produce 37,000,000 tons of plastic each year that ends up in landfills and in the water. We could convert this into fuel energy. I have done a cost analysis on the energy from plastic recycling.
A new GE unit cost less than $200. The membrane last 5 years and cost less than $50. The conditioning filters cost $40 and last 6 months. Well worth it.
Salt is a crystal formed by ionic bonds, there's no such thing as a salt molecule. They must be making holes small enough for a single sodium ion. Not sure why they need to tailor the holes for each chemical, though. Just make them a bit bigger than water molecules, right? Than I guess a second filter that's a bit smaller, to remove contaminants that are smaller...