Andre Geim [...] won the Noble prize for physics for the work.
That truly sounds like a prize fit for a king. Does it have the same kudos as the Nobel prize, though?
Graphene-creating boffins have discovered a new purpose for the wonder material - a teeny-tiny distillery. A team led by one of the Nobel prize-winning scientists who first made the world's thinnest and strongest material have now found out that graphene can stop air and other gases, but it lets water right through. Naturally …
Firstly, baffled as to how it would let water through but not helium through, given the size difference at play (only thought coming to mind is dipole nature of water?), but if this membrane does just let water through, and not anything else commonly found in drinking water, water purificaion options are surely about to get a boost?
That said distillery option is also pretty intriguing - I believe home distilleries were made illegal for their potential to go 'boom' - a flame/heat/pressure chamber free solution should therefore become viable...??
Home distilling was made illegal because of the lucrative tax levied on spirits. The reason given might have been health and safety but money was always the prime mover.
I was under the impression that helium always leaked because it was small and would always find any faults or interstitial cavities. If the graphene layer is a perfect lattice then there are no gaps as proven by its ability to block helium. Water molecules must therefore be 'passed' through the graphene by some sort of active process like a molecular level machine or catalyst.
It's not clear to me how the layers are orientated bu it looks as though the graphene sheets are stacked "vertically" |||||| so that the water has to move along between the sheets. If these have hydrophilic groups and have dimensions that just allows water to move through the spaces then other materials may well have problems as there will be a strong tendency for water to fill the spaces and repel any other molecules. In this situation the water will behave quite differently to bulk water - it'll be more like a sloppy ice where every water molecule that evaporates from the low humidity end will need to be replaced from the high end to maintain the energetics.
Eg, if it takes an hour to get a litre of water through a square meter of graphene, then its not going to be practical for domestic water/sewage purification.
Where as home spirit purification probably isn't going to matter if you want to wait a week for your Smirnoff Red to turn into Blue.
A liter-per-hour-per-square-meter of graphene-mat surface actually could work quite nicely for personal or household water filtering. In areas where clean water is hard to come by, if the graphene material can be produced cheaply enough, you could build a decent home water distillation system out of that.
According to a couple of references I just checked, it looks like an adult in hot, arid conditions performing a mix of moderate and heavy exertion needs around 2-3 liters of water per day. I have no idea if that's at all reliable, but if it is, then a system producing 1 liter per hour could handle the drinking-water requirements of 8 adults. Even when we allow for cooking water and a ration of cleaning water, that looks reasonable for a household.
Similarly, it'd probably work nicely for applications like camping, since you should be able to fold the mat for transportation.
Nice to see so many people thinking about how this can be used to benefit humanity, not just high boffinry. The trick will be to get the cost of manufacturing it low enough.
Drinking pure water generally isn't a problem; you can get enough of trace minerals through food, unless you're on an unusually restricted diet.
I'm guessing it could desalt water. However, we already have pretty decent (and much cheaper) filters to do that. The problem is pushing the water with enough pressure to get usable volumes on the other side (and using a filter able to withstand the pressure; a test that graphene is likely to fail.)
as I vaguely recall from 30 years ago. You'd *think* it would be ionically bonded, but IIRC it's actually weakly covalent, which is why it has some odd properties which are essential to life (why do you think the first indication of life astrobiologists use is liquid water). Also remember the "anomalous expansion of water "as it cools through 4C ?
That's not even the start of it. Water has a whole load of anomalous properties, due to various things, such as hydrogen bonding, its dihedral angle, dipole and the unbonded lone-pairs of electrons on the oxygen atom.
A good list of these is here:
Helium is atomic number 2, the second smallest element in existence besides Hydrogen at 1. It's atomic weight is a mere 4. And it's a noble gas, to boot, so it normally exists atomically. How can anything that allows water (which contains the much-larger oxygen atom--atomic number 8, weight 16) not allow helium. It can't be anything like a filter of sieve, since helium is smaller than water.
Gaps in the membrane are exactly "one water wide". There's NEVER any room for anything else. As soon as there's room for a fresh water molecule at a gap, it displaces anthing which might physically occupy the space. He (and everything else) gets left behind.
It's probably quantum too.
Er, that's 300º proof, not 300% proof........
%age measurements of alcoholic beverages are the %age by volume of alcohol in them. Thus 300% a) isn't possible and b) would kill you if it were.
Degrees of proof orginally measured the effect when gunpowder is soaked in whatever it is. If the gunpowder just still burns, you have 100 degrees of proof (which is a shade under 60% by volume alcohol). 300 degrees would remove your eybrows when you lit the gunpowder (and is also impossible, being about 175% abv alcohol if my maths is correct).
Stereotypically, Yank "proof" differs from British "degrees of proof".
Beer is measured by Original Gravity and you should be aiming for about 1100 for something really lethal and yet still drinkable.
It's Friday and you presented the opportunity to look again at booze strength measures, what did you expect?
I suppose the question that has to be asked is how quickly water will diffuse through a graphene membrane as opposed to current semi-permeable membranes, such as visking tubing used in dialysis. In other words, how much pressure is needed to get water through at a reasonable rate, and how robust is this stuff?
from how I understand the report, water gets through because it's a flat molecule and can slide between the sheets of graphene.
H2O is also a polar molecule, i.e. asymmetrical or a bit "L" shaped and not straight, so the hydrogen atoms are on one side are slightly positive charged and attract the slightly negatively oxygen atoms from adjacent water molecules (hydrogen bonding) so there's the possibility of giving the molecule behind a pull to help it line up and fit through the gaps. This would speed up the flow of water molecules across the membrane.
That's not enough to explain why helium doesn't get through. Helium is such a small and light atom that at normal temperatures (i.e a measure of kinetic energy) each atom has to be moving much faster than other atoms. Do we have the situation where something going so fast it bounces off the entrance to the gap between the sheets of graphene in the way that a pinball sent at full strength won't land in a hole? The probability of a direct hit on the gap in exactly the right direction is so low that it becomes effectively impermeable. And even then, the gaps are already filled with a nose-to-tail queue of water molecules waiting their turn to get through.
That interpretation is all dreadfully Newtonian (molecules aren't really made of balls joined by sticks) there could easily be a quantum mechanics explanation that works better. I'd predict something else is going on within the graphene sheets, probably involving delocalised (unbound) electrons and partial charge separation to interact with the polarised water molecules and draw them across the gap.
Whatever the mechanism is, it's an excellent piece of materials science and if it could become a desalination technology, it would be fantastic if it helped solve the biggest environmental and human problem - access to drinking water.
If helium can't get through, could the same also be true of hydrogen? If so we could have much lighter rockets and spaceplanes.
Perhaps I could have a space holiday before I die, without having to rob several banks.
There's also replacing/changing current reverse osmosis methods of course, but clean drinking water is much less fun. It takes an awful lot of electricity to push water through against the osmotic pressure, so there's huge potential to simplify the process and save energy. You often have to soften the water to avoid knackering the membranes.
But improving the lives of billions is surely a low priority in comparison to cheap, super-strong vodka and affordable spaceships...
There are several significant inventions we're still waiting for - could graphene be the missing piece in the jigsaw?
1) try firing a beam of neutrinos at some of the stuff. Who knows? You might invent a time machine. Or a Warp drive. It's worth a try.
2) Or what about concentrated light? There's got to be a way to turn a handful of laser pointers into a lightsabre, and graphene might just be it. Since the lightsabre sound is v. important, try firing laser and sound at graphene at the same time.
3) Maybe it reflects gravity. We already know you can write upside down using a graphite pencil. A hoverboard would be cool.
4) But not as useful as a teleporter. Not one of those boring quantum teleporters. A real one. Maybe a pair of entangled sheets of graphene would to the trick
Come on! This isn't about namby-pamby double-bluffed testing. It's about throwing science at the wall and seeing what sticks.
The whole problem of product viability in the advancement of ethyl for the auto industry is the verification of the most minuscule amounts of water. If this could be simply incorporated into the distilling of the Ethyl, the use of corn would be eliminated they could use basic organic matter and ferment it, the cost of corn is high and the viability of the production is dependent on the alcohol formation by using sugars in corn, sugar beats, and sugar cane. If the fermentation of any cellulose material was a possibly the amounts of water required to do so and the lower grade production wouldn't matter since the water would be easily strained off and producing a 100% ethyl for our autos. Cost would come down for producers, and their profits would increase. If we could blend 90% of our petrol with E85 instead of E10 we would lower fuel prices about $1.25 a gallon. It would also piss off the Arabs.
As a pipe and tank liner if this stuff can stop H2 diffusion that would be *very* impressive.
Caveats. Such an application would need large areas made *cheaply*, not one of graphenes strong points IIRC.
And of course there is the question of weather you *want* a Hydrogen economy given what a PITA it is to pressurize (backbone pipelines are not like house supplies) or liquify.
*if* you're still keen it cuts down some of the problems from *staggeringly* difficult (replacing *all* conventional piping with H2 resistant piping) to just very difficult (coating the existing stuff with an internal graphene layer).
because it not distillation.
Since its not distillation it may be legal to do at home until the gov waste more taxpayers money making it illegal that it would ever bring in in tax.
It should be noted that you can make really quite drinkable 20% proof wines at home with a little practice.
And if you want to get smashed quickly you want to water your shots down to 20% anyway so why not cut to the chase and check out how to make a high alcohol rice wine which can be ready to drink in 4 days.
Freeze distillation, or "jacking", tends to have one big drawback. Jacked liquor (like applejack--freeze-distilled apple brandy) tends to have more nasty fusel alcohols than you get with normal heat distillation. The practice is normally discouraged for anything but highly-traditional practices or for low-level jacking seen in ice beers and eisbock.
Biting the hand that feeds IT © 1998–2019