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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."
...you don't need a pressure source like you do for reverse osmosis?
Now we know what the water receptacles in Dune were made of.
Press and squeeze a hydraulic press of water through a few layers of graphene = no more salty water?
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.
But can it be used as a dessert topping?
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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?
The material they used was NOT graphene. It was graphene oxide.
graphene-based membranes are impermeable to all gases and liquids (vacuum-tight). However, water evaporates through them as quickly as if the membranes were not there at all.
Thanks for clarifying that. Anyway, this is a very amazing material.
Would be quite expensive, but letting water go thru and nothing else would save millons in remediation.
The membrane replacement cost is one of the main costs in making RO water. Energy costs are high too, but about the same order of magnitude.
So to save money the graphene membrane has to be cheaper or it has to use less energy to filter water.
I'm wondering if there are other things it lets through and not just water. Ammonia? Acetone?
Lets all the delicious moisture through, blocks the stuff you want blocked???
What about the Water Memory? Does this membrane erase all this information or is a there a mechanism to determine which information to be deleted? Would be an invaluable Material for all that homeopathy stuff...
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.
I'll see your senator, and I'll raise you two judges.
You are missing that the remaining liquid in the bottle evaporates, replacing the gas that left the bottle.
We hope your rules and wisdom choke you / Now we are one in everlasting peace
One of the problems with a "hydrogen economy" is storage as hydrogen leaks out of pretty much everything.
Wonder how well this blocks it.
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
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.
You're right, but details are needed.
Water intoxication can happen with either tap water or ultrapure water.
If you add hydration you need to add electrolytes or your system goes out of balance. Your body can handle only so much imbalance. As it goes too far out of whack, that's effectively water intoxication.
Drinking a glass of ultrapure probably won't hurt you, nor a glass of tap. But have a bunch of either in a short period and you will have a problem. Read the Wikipedia water intoxication article's "notable cases" section to get an idea of how much humans can handle.
Hm... When hydrogens separate from oxygens, do they always take their original electron back? Or are we getting a random one out of the, say, two valence electrons the molecule was using previously? If we're possibly getting a different electron, isn't there a constant swap going on in the universe, for perhaps all covalent molecular configuration changes?
That is, atoms reform constantly?
So, the hydrogen and oxygen atoms that make up water could themselves be relatively fresh.
If only they had an article you cold read that tells you how it works.
The Kruger Dunning explains most post on
This is what they said:
"In conclusion, unimpeded evaporation of water through Heleaktight membranes sounds next to impossible. The closest analogy is probably the permeation of protons (atomic hydrogen) through thin films of transition metals, the phenomenon known as superpermeability. To explain our experiments, we propose the model that can be summarized as follows. GO laminates contain 2D capillaries that, under ambient conditions, are filled with an ordered monolayer of water. A capillarylike pressure provides a sufficient flow to keep the exposed GO surface wet so that the observed permeability is effectively limited by the surface evaporation. Permeation of other molecules is blocked by the intercalating water and, simultaneously, by their shrinkage in low humidity. Such highly selective membranes can be used for filtration and separation. The results have implications for the use of graphene oxide in various applications (e.g., batteries), explaining why the observed surface areas are close to the theoretical maximum. The next challenge is to utilize the found phenomenon, possibly along the lines extensively discussed for membranes made from carbon nanotubes."
Don't ask me what it means though!