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Graphene Membranes Superpermeable to Water

Dr Max writes "Not only is graphene the strongest, thinnest and best conducting material known to man, it is now shown to have superpermeability with respect to water as well. This allows a membrane made with graphene to pass water right through it (PDF), while another atom or molecule (even helium) gets blocked. 'The properties are so unusual that it is hard to imagine that they cannot find some use in the design of filtration, separation or barrier membranes and for selective removal of water,' said one of the researchers."

16 of 292 comments (clear)

  1. Re:Does this mean... by imboboage0 · · Score: 4, Insightful

    After reading the second article, I'm not sure. I didn't read in detail, but they did some experiments with a pump. I'm not sure if it's required, but that is how they did it to research it.

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  2. Used to collect gifts from Shai-Hulud by geekopus · · Score: 5, Insightful

    Now we know what the water receptacles in Dune were made of.

  3. Super desalination? by Draconi · · Score: 5, Interesting

    Press and squeeze a hydraulic press of water through a few layers of graphene = no more salty water?

  4. Fresh water? by gmuslera · · Score: 5, Insightful

    So you could pass thru i.e. ocean or contaminated water and get fresh, drinkable, pure water on the other side? If that could scale could be great.

    1. Re:Fresh water? by rmstar · · Score: 4, Informative

      You can't drink pure H2O - it disrupts ionic balance, you could probably die from drinking too much pure water.

      What you need is to make sure you obtain the electrolytes and minerals from some other source to avoid insufficiency. Other than that, pure water is safe to drink.

    2. Re:Fresh water? by Tsingi · · Score: 4, Insightful

      Water is formed from hydrogen and oxygen. It is not inert, it decomposes and reforms constantly. So, no, water molecules are not at least 4.5 billion years old.

      The hydrogen and oxygen atoms that make up water, or at least most of them, may well be much older than that. Particularly the hydrogen, which may be over 13 billion years old.

    3. Re:Fresh water? by Russ1642 · · Score: 5, Informative

      Informative? How about flamebait. This is simply not true. Absolutely insanely pure water is just water. Your body doesn't react to a 0.0001% difference in dissolved solids. After a microsecond in your mouth the water is far from pure.

  5. Important detail by zAPPzAPP · · Score: 4, Informative

    It's not mentioned in the opener, but the article says it lets water "evaporate" through it.
    So it's not like you can just pour water on it, and let it drip through.

    I wonder if this just means steam can pass through it, or if it has to evaporate on the graphene for it to get through?
    If it was the former, then why are they wording it so complicated?

  6. graphene oxide, not graphene by THE_WELL_HUNG_OYSTER · · Score: 5, Informative

    The material they used was NOT graphene. It was graphene oxide.

  7. Re:Does this mean... by The+Grim+Reefer · · Score: 5, Informative

    ...you don't need a pressure source like you do for reverse osmosis?

    Even if it does not, I would think it would be much more resilient toward chlorine and iron. Perhaps it won't need as much pretreatment done to the water as a conventional film membrane requires. Currently most decent RO systems have a 10 micron sediment filter, followed by 5 and 1 micron carbon filters. If you have high iron content in the feed water, then you need a softener or some other way to reduce it prior to the sediment filter too. Since the three RO pre-filters typically need to be replaced every 6-12 months, they are the most frequent replacement item. A typical RO membrane last 2-5 years. Perhaps this would be lengthened too.

  8. Re:wonder substance by Bill+Hayden · · Score: 4, Funny

    No, just as a floor wax at this point.

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  9. Graphene Condom? by swb · · Score: 4, Funny

    Lets all the delicious moisture through, blocks the stuff you want blocked???

  10. If it blocks Helium by DickBreath · · Score: 4, Insightful

    If it blocks Helium this has very important applications.

    Helium molecules are very small. It is difficult to contain Helium gas in cylinders.

    There are even far more important applications for the global economy. It may finally be possible to make Helium balloons that don't leak the tiny molecules so quickly.

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  11. Re:Does this mean... by chill · · Score: 4, Insightful

    Yes, but here they're showing that the membrane allows WATER through but will stop HELIUM. If I'm not mistaken, helium molecules are smallerthan water molecules. That's the freakish quality.

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  12. Helium by TuringCheck · · Score: 4, Informative
    Actually the helium atom is the smallest possible molecule. The hidrogen atom is smaller but it forms H2 molecules which are much larger than a single atom, even if much lighter.

    Gaseous helium difuses through pretty much everything. These graphene membranes should have truly amazing properties.

    Armies of physicists will work years to explain such remarkable phenomenons. Neutrinos light than faster like just.

  13. Re:Does this mean... by Khyber · · Score: 4, Insightful

    Oxygen being in the center of a water molecule pretty much makes it larger than helium in ALL directions.

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