Graphene Membranes Superpermeable to Water

← Back to Stories (view on slashdot.org)

Graphene Membranes Superpermeable to Water

Posted by Soulskill on Friday January 27, 2012 @03:12AM from the it-slices-it-dices dept.

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."

235 of 292 comments (clear)

Min score:

Reason:

Sort:

Does this mean... by Anonymous Coward · 2012-01-27 03:15 · Score: 2, Insightful

...you don't need a pressure source like you do for reverse osmosis?
1. Re:Does this mean... by imboboage0 · 2012-01-27 03:20 · 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.
  
  --
  Honesty may be the best policy, but by process of elimination, dishonesty is the second best policy.
2. Re:Does this mean... by The+Grim+Reefer · 2012-01-27 03:31 · 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.
3. Re:Does this mean... by trout007 · 2012-01-27 03:32 · Score: 1
  
  There has also been studies showing you can make a selective filter by making nanotubes with the right diameter to let water through but not larger molecules. In addition because the walls are so "smooth" there is much less pressure to flow the water through then expected.
  
  --
  I love Jesus, except for his foreign policy.
4. Re:Does this mean... by X0563511 · 2012-01-27 03:32 · Score: 1
  
  Could you not use gravity? I have a filter on my counter that does just that.
  
  --
  For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
5. Re:Does this mean... by Tsingi · 2012-01-27 03:58 · Score: 1
  
  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.
  Even sub um thick membranes were strong enough to withstand a differential pressure P up to 100 mbar.
6. Re:Does this mean... by msheekhah · 2012-01-27 04:05 · Score: 2
  
  Can we use this for desalination? That would be epic.
  
  --
  Mark Anthony Collins
7. Re:Does this mean... by chill · 2012-01-27 04:05 · 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.
  
  --
  Learning HOW to think is more important than learning WHAT to think.
8. Re:Does this mean... by Cyberax · 2012-01-27 04:09 · Score: 2
  
  You do, of course. Otherwise you'll be able to create a perpetum mobile by using this membrane to filter out pure water and then using pure water to dilute brine (it produces energy) on the other side of the membrane.
9. Re:Does this mean... by Anonymous Coward · 2012-01-27 04:18 · Score: 3, Insightful
  
  You're using energy to get that water higher than it's final location, just like a pump.
10. Re:Does this mean... by slew · 2012-01-27 04:33 · Score: 3, Informative
  
  There has also been studies showing you can make a selective filter by making nanotubes with the right diameter to let water through but not larger molecules. In addition because the walls are so "smooth" there is much less pressure to flow the water through then expected.
  Although I doubt this orientation will allow for filtering out "helium" as the original posting.
  The mechanims that the original posting paper is speculating, it that the way they made the graphene oxide (not pure graphene) membrane, it is has embedded capilaries which when wet (filled with water) allow for nearly unimpeded transport of water, but when these capilaries dry out, their diameter constricts so that nothing gets through (even helium).
  So to contrast, the "tubes" are not rigid and the walls are not so "smooth" in this case, the "tubes" are sort of like chinese finger puzzles. When filled with water, allow water to pass easily, but when you try to pull the last bit of water out of them, the diameter constricts and nothing can get past.. Well maybe the chinese finger puzzle analogy was a bad one, but I couldn't think of anything else...
11. Re:Does this mean... by SuricouRaven · 2012-01-27 04:53 · Score: 1
  
  The laws of physics are rather strict on this account: You must, absolutly must, have a pressure source or some form of energy input. You can get energy out when you dilute a solution, and must put energy in to seperate them. It is possible it'll be more efficient though, so you don't need as much pressu.re
12. Re:Does this mean... by SuricouRaven · 2012-01-27 04:55 · Score: 1
  
  I did design a perpetual motion machine involving a really deep tube in the ocean with a RO membrane at the bottom, exploiting the slight density difference between fresh and salt water to produce the required pressure. I know it can't work, because if it did it would be producing energy from nothing, but I still can't figure out exactly why it wouldn't work.
13. Re:Does this mean... by Dr+Max · 2012-01-27 04:58 · Score: 2
  
  Exactly. Which doubles it's uses not only as a water filter but as a strong light weight container for almost anything. I'm thinking Airships that don't need re-filling and light weight gas tanks for fuel cells.
  
  --
  Rocket Surgeon.
14. Re:Does this mean... by marcosdumay · 2012-01-27 05:08 · Score: 1
  
  helium molecules are smallerthan water molecules
  That depends. The water molecule isn't round, it is larger on some dimensions than in other ones, and while interacting with the empty electronic states of graphene is may quite well get smaller than helium on some directions.
  
  --
  Rethinking email
15. Re:Does this mean... by sexconker · 2012-01-27 05:28 · Score: 1
  
  Can we use this for desalination? That would be epic.
  Or how about cleaning up oil spills?
16. Re:Does this mean... by ArsenneLupin · 2012-01-27 05:41 · Score: 1
  
  The mechanims that the original posting paper is speculating, it that the way they made the graphene oxide (not pure graphene) membrane, it is has embedded capilaries which when wet (filled with water) allow for nearly unimpeded transport of water, but when these capilaries dry out, their diameter constricts so that nothing gets through (even helium).
  ... which would mean that helium dissolved in water would be able to pass (because there would still be enough water molecules to prop them tubes open), making it useless for filtering helium out of water.
17. Re:Does this mean... by AdrianKemp · 2012-01-27 05:57 · Score: 2
  
  It'd actually be awful -- it might filter the oil out but it'd take all of the gases/salt/etc out of the water too.
  The XPrize winning oil cleaner is probably way faster anyways since it doesn't rely on filtration (which is inherently slow)
18. Re:Does this mean... by RussellSHarris · 2012-01-27 05:59 · Score: 2
  
  That might not be much of a problem. Helium is the least water-soluble monatomic gas. At STP (0 C, 1 atm), the solubility of helium is 1.7 ppm.
  http://www.engineeringtoolbox.com/gases-solubility-water-d_1148.html
  Helium pretty much just doesn't like staying anywhere, including in water.
19. Re:Does this mean... by trout007 · 2012-01-27 06:04 · Score: 1
  
  I think by Physics you need it to input energy to make this work.
  There are RO membranes that are used for power generation using salt water and fresh water kind of like a fuel cell.
  If this required no power you could have a perpetual motion machine.
  
  --
  I love Jesus, except for his foreign policy.
20. Re:Does this mean... by Khyber · 2012-01-27 06:12 · Score: 4, Insightful
  
  Oxygen being in the center of a water molecule pretty much makes it larger than helium in ALL directions.
  
  --
  Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
21. Re:Does this mean... by Khyber · 2012-01-27 06:13 · Score: 1
  
  Read up on Ocean Thermal Energy Conversion.
  Brine is crap, use temperature gradients instead.
  
  --
  Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
22. Re:Does this mean... by jasno · 2012-01-27 06:44 · Score: 2
  
  Yeah but you could use tidal action... Sure, it limits the rate of clean water, but it's free.
  Hell, if you had a cistern below sea-level then gravity would do the work for you - you'd only expend energy to pump up the water. Humans are used to that, so it's really like having free groundwater.
  
  --
  
  http://www.masturbateforpeace.com/
23. Re:Does this mean... by Grishnakh · 2012-01-27 07:18 · Score: 2
  
  I wonder if that's one of those things that really would work, but not because it's perpetual motion, but instead because it's taking energy out of the system that's already there. For instance, look at wind power: just stick up a windmill in a windy place and you get free energy. Except that's not quite free: there's energy in the atmosphere, which is causing this wind, so your windmill is removing (a very small amount of) energy from the atmosphere and converting it to electricity. It works ok because of the scales involved, but if you saturated the globe with windmills, you'd probably cause a giant ecological or climate problem. Also, all this energy in the atmosphere is coming from the sun, so ultimately all you're doing is leaching off of the sun's waste heat in an indirect manner. Same goes for those tidal power generators; if we saturated the ocean floor with those things, it'd probably cause some massive problems (like stopping the ocean currents perhaps).
24. Re:Does this mean... by Onymous+Coward · 2012-01-27 07:21 · Score: 1
  
  Maybe they just had a drier environment outside the test jar. Does that count as a pressure difference?
25. Re:Does this mean... by bky1701 · 2012-01-27 07:52 · Score: 1
  
  Most of the salts would be insoluble in oil, so if it works well enough, they could be put right back in.
  
  --
  Great Intellect...
26. Re:Does this mean... by nullchar · 2012-01-27 08:23 · Score: 1
  
  Right, but no one wants to filter helium from water, they want to filter all sorts of other stuff from water.
  But if the membrane is dry, perhaps this could make kick-ass graphene blimps!
27. Re:Does this mean... by HiThere · 2012-01-27 08:30 · Score: 2
  
  That's not a forbidden class of perpetual motion machine. It ultimately gets it's energy from the sun. And you are quite limited in the amount of energy that you can extract that way. I've never designed one, but there are a few analogous systems that are (or were, before solar power got cheaper) operating on remote islands. They were all test systems and none of them was cost effective, but that's more a design and materials problem than anything basic.
  IIRC there was one system that cost several thousand (not million!) dollars to build, and which could produce over 50 watts (don't remember how much). And it also had maintenance expenses. (Things immersed in salt water tend to.)
  I think the concept has been abandoned, but (some of) the pilot projects actually did work.
  
  --
  
  I think we've pushed this "anyone can grow up to be president" thing too far.
28. Re:Does this mean... by HolyCrapSCOsux · 2012-01-27 08:43 · Score: 1
  
  Does capillary action require added energy?
  
  --
  0xB315AA8D852DCD3F3DCA578FD2E0BF88
29. Re:Does this mean... by Unordained · 2012-01-27 08:43 · Score: 2
  
  So, if it rained on the blimp, would the water fall all the way through? When it flies through a cloud -- is the cloud really flying through the blimp?
30. Re:Does this mean... by _0xd0ad · 2012-01-27 08:54 · Score: 1
  
  No - water is in a lower energy state after it has risen in a narrow space due to capillary action. You'd have to add energy to get it back out of the narrow space.
31. Re:Does this mean... by Fned · 2012-01-27 09:43 · Score: 1
  
  I did design a perpetual motion machine involving a really deep tube in the ocean with a RO membrane at the bottom, exploiting the slight density difference between fresh and salt water to produce the required pressure. I know it can't work, because if it did it would be producing energy from THE SUN, but I still can't figure out exactly why it wouldn't work.
  FTFY.
  You're welcome.
32. Re:Does this mean... by treeves · 2012-01-27 10:29 · Score: 1
  
  I believe you are correct, but one should keep in mind that simply having a higher atomic number (number of protons and therefore number of electrons in a neutral atom) does not mean a higher atomic radius. In fact, atomic radii decrease as one goes from left to right on a given row on the periodic table.
  see http://www.webelements.com/helium/atom_sizes.html
  
  --
  ...the future crusty old bastards are already drinking the Kool-Aid.
33. Re:Does this mean... by treeves · 2012-01-27 10:32 · Score: 1
  
  In fact, if you had water enriched with helium, I'm sure you could successfully market it as some life-enhancing beverage. "makes you lighter than air!"
  
  --
  ...the future crusty old bastards are already drinking the Kool-Aid.
34. Re:Does this mean... by morethanapapercert · 2012-01-27 11:20 · Score: 1
  
  Which is why the guys who seriously try to invent such devices in their garage or basement often use the term Over Unity. There are things that many people might consider perpetual motion, certain for any considerations within a human lifetime, such as two bodies in orbit around each other, a single body travelling through space and so on. The thing is; they can't be harnessed for energy. What the people with the shaky grasp of physics are trying to do is create a device that outputs more energy than it took to get going/takes to keep going.
  
  --
  I need a wheelchair van for my son. Help me get the word out. https://www.gofundme.com/wheelchair-van-for-jj
35. Re:Does this mean... by thegarbz · 2012-01-27 11:52 · Score: 2
  
  That's a narrow view of what is in water. Distilled / deionised water is incredibly bad for you. We can't just mix H2O and NaCl, it won't support life. Water needs a long list of nutrients and other molecules like dissolved oxygen before it can support life.
  I know its not relevant at the scale we're talking, but I'm just pointing it out, there's no point in adding the salt back by itself.
36. Re:Does this mean... by marcosdumay · 2012-01-27 11:54 · Score: 1
  
  That is true in isolation, but can change while interacting with something. While traversing the graphene it may quite well get smaller than the helium. Other thing that can happen is to the empty space at the graphene to grow when near a whater molecule...
  To be short, when you put two molecules toghether they may become quite different from what they are when far apart.
  
  --
  Rethinking email
37. Re:Does this mean... by geekoid · 2012-01-27 12:49 · Score: 1
  
  It would take the water out and leave the oil and other matter..so... no.
  
  --
  The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
38. Re:Does this mean... by geekoid · 2012-01-27 12:54 · Score: 1
  
  or gravity.
  Meaning you put it lower then the source. No pump is used to get water to my house...usually.
  When the turbidity is high they turn on the ground well pumps, but most of the time the system is just gravity.
  
  --
  The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
39. Re:Does this mean... by tragedy · 2012-01-27 16:21 · Score: 1
  
  What happens to those airships when it rains?
40. Re:Does this mean... by Dr+Max · 2012-01-27 17:50 · Score: 1
  
  Water is pretty easy to stop, plastic is pretty good at it.
  
  --
  Rocket Surgeon.
41. Re:Does this mean... by tragedy · 2012-01-27 18:44 · Score: 1
  
  I suppose it could work with a multi-layer solution. I was mostly just being facetious about making a pure graphene envelope. The other big problem I didn't bother bringing up is whether or not it's even possible to make an envelope out of graphene because of its unusual properties. Large sheets of it may not be very physically stable. Sandwiching it between layers of other materials might work really well, however. So, off the cuff mocking of the idea completely withdrawn. I didn't think.
42. Re:Does this mean... by Trahloc · 2012-01-27 18:50 · Score: 1
  
  The energy of putting it in the container against gravity could be all the energy needed so it dribbles out... assuming its not lighter than whatever it's mixed with.
  
  --
  The Goal: A long simple life filled with many complex toys.
43. Re:Does this mean... by SuricouRaven · 2012-01-27 20:39 · Score: 1
  
  As so many people are trying to tell me it wouldn't work for reasons so obvious I'd already dismissed them, I'll explain exactly what I thought of.
  
  First, this doesn't involve the sun at all. Remove the sun. You do need the earth, because you need gravity. You then need two very, very tall columns of fluid: One water, one brine. The more saturated the salt solution, the shorter your giant column need be... but it's still got to be big.
  
  Saltwater is denser than fresh, so as you go down the columns the pressure difference between them increases. At the very bottom, the salt column is exerting substantially more pressure than the fresh. So much so that you could run RO off it: Shifting water from the salt column into the fresh, and removing the salt in the process. This would cause the fresh column to rise and the salt to fall, so at the top you have a height difference. All you need to do this is direct the top of your fresh column into the salt column, and you have a perpetual cycle of water. Attach a turbine, and you have free energy. It's completly impractical - you'd have to build it in a deep ocean trench and probably get enough power to run a LED - but I can't find any reason it wouldn't work. I know there's one, because the alternative is that I've just earned myself a noble prize in phyics, I just can't find it.
44. Re:Does this mean... by SuricouRaven · 2012-01-27 20:41 · Score: 1
  
  The Standard Rules of Perpetual Motion Contests state that you are allowed to ignore maintainance concerns of real materials in order to focus on the basic physics involved. You can also make friction arbitarily small for the same reason. You may also assume an infinite budget.
45. Re:Does this mean... by Cyberax · 2012-01-28 12:21 · Score: 1
  
  Yes, I've been thinking about it. I think I've found what is the problem with your solution.
  Suppose that you have a pipe of length L, with brine density D1 and fresh water density D. So the pressure differential at the bottom of the pipe would be L*(D1-D) - it can be arbitrarily big, certainly big enough to overcome the osmotic pressure. Right?
  That bit probably is wrong. Osmotic pressure is not constant, it rises with the pressure on the 'freshwater' side of the membrane. So you can not create enough pressure differential just by submerging a pipe with semi-permeable membrane.
46. Re:Does this mean... by SuricouRaven · 2012-01-29 08:47 · Score: 1
  
  I think you're onto something there. I've still not quite got it - I found the equasion for osmotic pressure on wikipedia, and there seems to be no dependance upon absolute pressure... but I'm not confident I properly understand the math involved here, and that does look like a promissing place to look for the fatal flaw in the design that will seperate me from that shiny noble prize I would so like to hang on my wall.
47. Re:Does this mean... by sexconker · 2012-01-30 11:59 · Score: 1
  
  It'd actually be awful -- it might filter the oil out but it'd take all of the gases/salt/etc out of the water too.
  Pump oil + water onto ship.
  Run through these filters.
  Dump H2O back into ocean because who gives a shit whether or not it has salt or gas? It'll mix back in with the ocean which has plenty.
48. Re:Does this mean... by sexconker · 2012-01-30 11:59 · Score: 1
  
  It would take the water out and leave the oil and other matter..so... no.
  Uh, pump dirty water onto boat, filter, dump clean ater back into ocean, carry oil + shit to processing plant.
Oil nets anyone? by Anonymous Coward · 2012-01-27 03:21 · Score: 1

Possibly a new way to collect oil spills no? Interesting potential.
1. Re:Oil nets anyone? by X0563511 · 2012-01-27 03:34 · Score: 1
  
  No, it would strip out -everything- except the water. Including the salts, I expect.
  
  --
  For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
2. Re:Oil nets anyone? by Hamsterdan · 2012-01-27 04:06 · Score: 1
  
  Wouldn't it be less harmful to put non-salt water back in than leave oil in the water? Depending on the size of the spill, it might just dilute salt concentration a little (amongst other things).
  
  --
  I've got better things to do tonight than die.
3. Re:Oil nets anyone? by ceoyoyo · 2012-01-27 05:14 · Score: 1
  
  Oil molecules are MUCH larger than water molecules, so conventional filters would probably work better. You would't have to deal with your filter getting clogged up with salts in addition to oil.
Used to collect gifts from Shai-Hulud by geekopus · 2012-01-27 03:21 · Score: 5, Insightful

Now we know what the water receptacles in Dune were made of.
1. Re:Used to collect gifts from Shai-Hulud by wbr1 · 2012-01-27 05:48 · Score: 1
  
  You leave the little makers out of this. The Lisan al-Gaib has spoken.
  
  --
  Silence is a state of mime.
2. Re:Used to collect gifts from Shai-Hulud by HiThere · 2012-01-27 08:40 · Score: 1
  
  You don't need anything that fancy. In the book they operated on the temperature differential between the inside of a cave and the daytime desert. Should work. The problem is to hold onto the water after you've collected it. (I have trouble believing in still-suits. I think they would result in rapid overheating.)
  To make a still-suit that works you need to have REALLY GOOD BATTERIES and use solar cells to collect the electricity to charge them, then build a refridgerator into the suit, which makes some part of the suit REALLY HOT. Possibly the boots? But then you'ld BETTER never stop walking, or stand on a large sheet of metal. The back has a larger area for release, so it wouldn't need to get as hot. Or if you want to get *really* fancy, and have the right materials, you could use the output of the refridgerator (heat pumt) to boil sand, and disperse the heat as a gas. But you don't want to chance breathing that vapor! So you need a mask on the inhale as well as on the exhale.
  
  --
  
  I think we've pushed this "anyone can grow up to be president" thing too far.
3. Re:Used to collect gifts from Shai-Hulud by geekoid · 2012-01-27 12:59 · Score: 1
  
  if the material moved sweat from your body, it would have a cooling effect.
  
  --
  The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
4. Re:Used to collect gifts from Shai-Hulud by Shadow+of+Eternity · 2012-01-27 15:18 · Score: 1
  
  Right, so when the sweat is removed from the surface of your body conducting heat with it... where's that heat go? How does the suit dissipate it?
  
  --
  A bullet may have your name on it but splash damage is addressed "To whom it may concern."
Super desalination? by Draconi · 2012-01-27 03:22 · Score: 5, Interesting

Press and squeeze a hydraulic press of water through a few layers of graphene = no more salty water?
1. Re:Super desalination? by felipekk · 2012-01-27 03:54 · Score: 1
  
  Better yet, no more polluted water!
2. Re:Super desalination? by Anne_Nonymous · 2012-01-27 04:15 · Score: 2
  
  Plus we can sell the harvested toxic waste to Hormel, or Hollywood, or Congress, or somebody.
3. Re:Super desalination? by Adriax · 2012-01-27 04:15 · Score: 1, Informative
  
  Water so completely pure you'd have to introduce contaminants just to make it safe to drink.
  http://en.wikipedia.org/wiki/Water_intoxication
  
  --
  I don't suffer from insanity, I enjoy every minute of it!
4. Re:Super desalination? by alienzed · 2012-01-27 04:31 · Score: 1
  
  Graphenated water? Mmm, nanoparticles
  
  --
  Never say never. Ah!! I did it again!
5. Re:Super desalination? by Chuckstar · 2012-01-27 04:36 · Score: 2
  
  You won't get water intoxication merely by drinking pure water. Regular drinking water contains such low proportions of minerals that, from a physiological perspective, drinking water is effectively pure water. The main problem with pure water is that it doesn't taste "right". If you've ever tried drinking distilled water... yuck.
6. Re:Super desalination? by Tim4444 · 2012-01-27 04:41 · Score: 1
  
  I understand that one of the current problems with desalination filtering is that the salt left behind clogs up the filter fairly quickly. Hopefully researchers will test to know for sure, but this may well suffer from the same problem. The other problem is that the water wants to be with the salt - ie. it's an energetically stable state. You have to put in some energy (usually via pressure) to get it through a filter and away from the salt. Compare that to simply filtering out fine particulates that might settle out on their own given enough time. I would imagine a more practical use might be in prepping water for chip (read IC) fab plants where the water used must be extremely pure. I'm just guessing here - it may still not meet the requirements with filtration alone.
7. Re:Super desalination? by gman003 · 2012-01-27 05:00 · Score: 1
  
  At the very least, it could be used for agriculture. Plants don't exactly care how water tastes. It could probably be used in soft drinks as well. Plus making cooling water that doesn't corrode stuff or build up residue - I can imagine this being used in nuclear reactors.
  If it really is as simple as "run water through graphene sheets, get 100% pure hydrogen oxide", there's no limit to how many places it could be used.
8. Re:Super desalination? by The+Good+Reverend · 2012-01-27 05:41 · Score: 1
  
  Plenty of plants also use the minerals dissolved in water, the same way we do. Ionized water certainly has its uses, but most plants don't need it.
9. Re:Super desalination? by The+Good+Reverend · 2012-01-27 05:44 · Score: 1
  
  Sorry, that should be distilled, not ionized.
10. Re:Super desalination? by RussellSHarris · 2012-01-27 05:46 · Score: 3, Informative
  
  Please, stop spreading the FUD. Regular tap water can just as well cause water intoxication if you drink too much of it, and ultra-pure water is by no means unsafe to drink.
11. Re:Super desalination? by chihowa · 2012-01-27 06:16 · Score: 1
  
  Please, stop spreading the FUD. Regular tap water can just as well cause water intoxication if you drink too much of it, and ultra-pure water is by no means unsafe to drink.
  It does taste weird, though. Although the weirdest tasting water I've ever tried was D2O (which was also ultra pure).
  
  --
  If you want a vision of the future, imagine a youtube comments section scrolling - forever.
12. Re:Super desalination? by rrohbeck · 2012-01-27 06:43 · Score: 1
  
  Mixing fresh water with brine releases quite a bit of energy as heat. Hence you will need at least that amount to separate fresh water from ocean water. Graphene might make that more practical than current membranes but it won't save energy. Energy cost is the big problem for desalination.
  
  --
  thegodmovie.com - watch it
13. Re:Super desalination? by marcosdumay · 2012-01-27 06:54 · Score: 1
  
  If your filter is one atom thick, there is nowhere you can accumulate any amount of material to clog anything. But it also restrict the pressure you can apply to it... You can increase the pressure again if you use several filters, one behind the other, but them you'll have to wash all of them, otherwise they'll clog.
  So, potentialy, that can remove the problem. In practice, I have no idea.
  
  --
  Rethinking email
14. Re:Super desalination? by Grishnakh · 2012-01-27 07:23 · Score: 1
  
  Exactly; it's safer to drink ultra-pure water instead of tap water in fact since it doesn't have the impurities tap water does (albeit in small concentrations, unless they screwed up at the water-treatment facility, which does happen from time to time). The problem is that it tastes awful; go buy a gallon of distilled water and try for yourself. If you did drink ultra-pure water, you'd probably want to take a daily calcium and magnesium supplement too, unless your food has enough of that.
15. Re:Super desalination? by thegarbz · 2012-01-27 12:00 · Score: 1
  
  No more anything water. The way I read this the filtering would result in pure H2O which is not really drinkable...
16. Re:Super desalination? by ill+dillettante · 2012-01-27 23:30 · Score: 1
  
  I drink Millli-Q water (ultra pure) water all the time and it does not taste awful. I agree it does not taste like tap water - the closest I can describe it as is liquid air, Actually I encourage all scientists to drink their own Milli-Q water as it is any easy way to pick up if there is a problem with your lab water. It is really easy to ruin experiments with bad water and drinking it will let you know when it has gone bad (i.e. time to change the filters).
  
  --
  Automated DNA sequencing software
17. Re:Super desalination? by tibit · 2012-01-28 16:56 · Score: 1
  
  I think that industrial grade desalination is done using flash vaporization where the salt water vaporizes while not being in contact with anything solid (nothing to clog). The saltwater is pressurized and overheated, still a liquid. It's then directed via nozzles into a large container. It leaves a nozzle at a very high pressure, the pressure drops as you get away from the nozzle, eventually it's low enough that the water vaporizes. The salt becomes a solid powder, suspended in water vapor -- it's akin to what you'd have in a sandstorm, only much hotter, and the gas is different. You then separate the two, condense the water vapor into fresh water (and recover some heat while doing so), and that's it.
  
  --
  A successful API design takes a mixture of software design and pedagogy.
Fresh water? by gmuslera · 2012-01-27 03:23 · 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 Dave+Whiteside · 2012-01-27 03:27 · Score: 1
  
  Recycled water never tasted so good. [or at all]
  
  --
  who where what when now?
2. Re:Fresh water? by trout007 · 2012-01-27 03:30 · Score: 2
  
  Or you could mine salt by dragging a net of graphene behind a boat.
  
  --
  I love Jesus, except for his foreign policy.
3. Re:Fresh water? by CastrTroy · 2012-01-27 03:32 · Score: 1, Interesting
  
  If it's really only letting water through, you'd still have to add minerals in at the other end. Last I checked, drinking distilled pure water is probably as bad as drinking salt water.. With salt water your body accumulates too much salt. With distilled water. all the minerals (that your body needs to function) get picked up by the water. However it it works well, it would be simple to add minerals back in after everything had been extracted.
  
  --
  
  Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
4. Re:Fresh water? by iggymanz · 2012-01-27 03:38 · Score: 3
  
  nonsense, that (water intoxication) only happens if you drink too much water (whether 100% pure or not)
5. Re:Fresh water? by rmstar · 2012-01-27 03:39 · 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.
6. Re:Fresh water? by The+Grim+Reefer · 2012-01-27 03:40 · Score: 1
  
  You can't drink pure H2O - it disrupts ionic balance, you could probably die from drinking too much pure water.
  Yes you can. You can also die from drinking too much tap water as it also upsets the ionic balance. I would guess that this would occur with very slightly less pure water. I used to keep coral and other saltwater invertebrates, so I have a pretty good filtration system that uses a combination of carbon filtration, reverse osmosis and cation/anion deionization resins. I've been drinking it for 25+ years and so has my family. I'm pretty certain that we're all alive and well.
7. Re:Fresh water? by RussellSHarris · 2012-01-27 03:40 · Score: 2
  
  You can't drink pure H2O
  Stop spreading the FUD.
  
  it disrupts ionic balance
  If you're eating properly you will get plenty of electrolytes from your food.
  
  you could probably die from drinking too much pure water
  And you could probably die from drinking too much pure Gatorade. Your point?
8. Re:Fresh water? by countertrolling · 2012-01-27 03:46 · Score: 3, Informative
  
  All water is recycled. Every water molecule on the planet is at least 4.5 billion years old. All the dinosaur turds and spuge have been filtered out.
  
  --
  For justice, we must go to Don Corleone
9. Re:Fresh water? by The+Grim+Reefer · 2012-01-27 03:49 · Score: 2
  
  And you could probably die from drinking too much pure Gatorade. Your point?
  That sounds like something that Brawndo can use in a future advertising campaign.
10. Re:Fresh water? by tzot · 2012-01-27 03:54 · Score: 3, Insightful
  
  The atoms might be at least 4.5 billion years old, but not *every* molecule of water is of that age.
  
  --
  I speak England very best
11. Re:Fresh water? by Russ1642 · 2012-01-27 03:54 · Score: 1
  
  Are you kidding? Really? I must know. I know people will go for oxygenated water and such so someone thinking that they can't drink pure water wouldn't surprise me. It'd upset me though to know there are such stupid people out there.
12. Re:Fresh water? by Anonymous Coward · 2012-01-27 03:56 · Score: 1
  
  In fact, I might have been pissing in your water bottle right....... now...........
13. Re:Fresh water? by DigiShaman · 2012-01-27 03:56 · Score: 2
  
  Do both. You can now sell fresh water and salt. It's two markets in one to profit from.
  
  --
  Life is not for the lazy.
14. Re:Fresh water? by felipekk · 2012-01-27 03:56 · Score: 2
  
  Not literally every water mollecule. There's A LOT of chemical reactions that produce water as a product or byproduct. If I remember my chemistry classes correctly, these water molecules were possibly created.
15. Re:Fresh water? by cunniff · 2012-01-27 03:58 · Score: 3, Insightful
  
  Spend a little time thinking about it, and you will realize that distilled water urban legend is silly. In your mouth, it is mixed with saliva and mucous and whatever else is stuck to your teeth, gums, and tongue. The instant it hits your stomach, it is mixed with stomach acids and whatever you ate recently. I.e. it is no longer pure distilled water. From there, the molecules wander through your body like any other water molecule. Distilling water does not give its component molecules magic properties.
16. Re:Fresh water? by WillgasM · 2012-01-27 04:00 · Score: 1
  
  It's easier to overdose on distilled water than regular tap water. From what I've read, this process seems to make Ultra Pure Water (UPW) which leeches minerals even faster. UPW is often used in manufacturing electronics. Currently, the process for making UPW starts with RO filtered water then subjects it to 12 more steps of filtration with the last step being a 20nm filter. Drinking a glass of the stuff won't kill you, but over a prolonged time it almost certainly would.
17. Re:Fresh water? by Anonymous Coward · 2012-01-27 04:02 · Score: 3, Funny
  
  He's not spreading FUD. Pure H2O is possibly the most corrosive chemical in the universe and IS certainly the most corrosive chemical in the known universe. The second the stuff hits your mouth it'll leech all the minerals from your teeth. God only know what it would do to the soft tissues, but you can be certain the sodium will be gone and the cell membranes will collapse due to the saline imbalance. Nerves would certainly be rendered useless in the vicinity of the water contact as well. It would literally be safer to drink lye.
  I remember in college a problem we had in the physics department, they were using super clean water because they needed to minimize diffraction through it, and within a couple hours the vessel holding the water shattered because the water had sucked all the minerals out of the glass.
  Don't underestimate the power of the hydrogen bond.
18. Re:Fresh water? by Tsingi · 2012-01-27 04:05 · 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.
19. Re:Fresh water? by chill · 2012-01-27 04:07 · Score: 1
  
  Brawndo! It's got what plants crave! It's got ELECTROLYTES!
  http://video.google.com/videoplay?docid=-4056644458485033927
  
  --
  Learning HOW to think is more important than learning WHAT to think.
20. Re:Fresh water? by chichilalescu · 2012-01-27 04:12 · Score: 1
  
  if you only drink pure water, and you only use pure water for cooking (with otherwise normal ingredients for a reasonably healthy diet), you will be perfectly fine.
  if you're talking about a specific scenario (i.e. running a marathon or something similar), I would have to ask a doctor, but you should also mention this in your post.
  
  --
  new sig
21. Re:Fresh water? by VIPERsssss · 2012-01-27 04:15 · Score: 1
  
  Fresh water, salt, AND anchovies.
  
  --
  We are eternal, all this pain is an illusion.
22. Re:Fresh water? by CSMoran · 2012-01-27 04:24 · Score: 1
  
  Every water molecule on the planet is at least 4.5 billion years old.
  Are you sure?
  
  I disinctly remember lighting up a test-tube full of hydrogen during chemistry in seventh grade. The water that this brief explosion produced could be seen on the walls of the test-tube. This happened some 20 years ago, not 4.5E9.
  
  --
  Every end has half a stick.
23. Re:Fresh water? by Joce640k · 2012-01-27 04:25 · Score: 1
  
  Nope. There's a whole load of new-agers out there who drink nothing but distilled water. Google "water distiller" and you'll see.
  The secret is that almost all foods have a lot of water in them - with some diets you might not even need to drink extra water!
  The water in the food isn't distilled. Some foods even have their own minerals, too...
  
  --
  No sig today...
24. Re:Fresh water? by Adriax · 2012-01-27 04:29 · Score: 1
  
  Related I would assume.
  http://en.wikipedia.org/wiki/Self-ionization_of_water
  
  --
  I don't suffer from insanity, I enjoy every minute of it!
25. Re:Fresh water? by Joce640k · 2012-01-27 04:34 · Score: 1
  
  Last I checked, drinking distilled pure water is probably as bad as drinking salt water.
  Where did you 'check' that? Maybe you need better sources.
  There's loads of people out there who drink nothing but distilled water believing it's healthier - Google "home water distiller" for proof.
  
  --
  No sig today...
26. Re:Fresh water? by MikeyC01 · 2012-01-27 04:35 · Score: 1
  
  Back in the 70s my grandfather's doctor told him he should start drinking distilled water. Sparkletts (http://www.sparkletts.com) delivered (and still delivers) 5 gallon bottles of distilled water so it certainly can't be *that bad* for you. Given our litigious society I would imagine that distilled water at the grocery store would either be plastered with warning labels or only available behind the counter with proof of ID :)
27. Re:Fresh water? by Chuckstar · 2012-01-27 04:42 · Score: 2
  
  Regular drinking water has such a small amount of dissolved minerals in it that, from a physiological perspective, it's effectively pure. If 10 gallons of tap water would give you water intoxication, then 9.99 gallons of pure distilled water would have the same effect. That's probably well within the error range of measuring the effect of the intoxication in the first place.
28. Re:Fresh water? by fnj · 2012-01-27 04:43 · Score: 1
  
  Nonsense. I mean, lack of minerals might kill you if you NEVER ATE FOOD which contains far more minerals than any drinking water.
29. Re:Fresh water? by sydneyfong · 2012-01-27 04:43 · Score: 1
  
  Isn't that simple diffusion rather than osmosis?
  
  --
  Don't quote me on this.
30. Re:Fresh water? by Russ1642 · 2012-01-27 04:45 · 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.
31. Re:Fresh water? by Baloroth · 2012-01-27 04:45 · Score: 1
  
  The problem, I think, is if you only drink distilled water, the electrolytes and minerals that leave your system in urine aren't being replaced as fast as they are when you drink tap water. Sure, you'll get some from food, but much less than normal. This could be a major issue, especially if you are drinking a lot of water. I.e. drinking a lot of distilled water could result in electrolyte depletion that would not happen with tap water. But this is probably something very few people will ever be in danger of doing.
  
  --
  "None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
32. Re:Fresh water? by Chuckstar · 2012-01-27 04:53 · Score: 1
  
  I call BS. I challenge you to experimentally show anything you've claimed.
33. Re:Fresh water? by Rogerborg · 2012-01-27 04:55 · Score: 3, Funny
  
  Fresh water, salt, AND anchovies.
  And mermaids. You ever had sex with a mermaid? Blows your mind, man. I can't even begin to imagine what it would be like to do a live one.
  
  --
  If you were blocking sigs, you wouldn't have to read this.
34. Re:Fresh water? by GameboyRMH · 2012-01-27 04:58 · Score: 1
  
  I imagine the water doesn't stay super-pure for long either, after it follows a Big Ma^H^H vegan soy burger that tastes like dust into your stomach where all the other food you ate in the last couple hours is.
  
  --
  "When information is power, privacy is freedom" - Jah-Wren Ryel
35. Re:Fresh water? by RussellSHarris · 2012-01-27 05:02 · Score: 2
  
  He's not spreading FUD.
  Yes, it most definitely is FUD, and he was spreading it, though not nearly as thickly as you.
  
  Pure H2O is possibly the most corrosive chemical in the universe and IS certainly the most corrosive chemical in the known universe.
  I think the phrase you're looking for is "universal solvent". Oxygen is the most corrosive chemical in the universe, AFAIK. Solvent != corrosive.
  
  The second the stuff hits your mouth it'll leech all the minerals from your teeth.
  Utter bullshit. The leaching process would be so slow that you'd have to leave a tooth in a glass of DI water for a long time before any substantial amount of minerals were leached out of it.
  
  God only know what it would do to the soft tissues, but you can be certain the sodium will be gone and the cell membranes will collapse due to the saline imbalance.
  Water passes through a cell membrane much more easily than those ions, so no. Osmatic pressure would cause the cells to fill with water until they burst, but regular tap water will do the same thing. It would not instantly suck all the ions out of your cells, by any stretch of the imagination.
  
  It would literally be safer to drink lye.
  Why don't you go and do that, moron. Meanwhile, I'll be drinking RO water, just about as pure as it can be made.
  
  I remember in college a problem we had in the physics department, they were using super clean water because they needed to minimize diffraction through it, and within a couple hours the vessel holding the water shattered
  Correlation != causation. I'm sure plenty of people have kept super-pure water in glass vessels without experiencing that problem, so the onus is on you to prove what you claimed next:
  
  because the water had sucked all the minerals out of the glass.
36. Re:Fresh water? by Joce640k · 2012-01-27 05:05 · Score: 1
  
  Whoosh!
  
  --
  No sig today...
37. Re:Fresh water? by WillgasM · 2012-01-27 05:13 · Score: 1
  
  I can't tell if you're a troll or just simple. 1. Reread my post; I said it's "easier" not "guaranteed." 2. No durr, the water in food isn't distilled. I would hope the distillation process would remove particles even smaller than a hot dog. 3. There is an order of magnitude difference between distilled water and UPW. 4. Usually when you talk about water toxicity, you're talking about an electrolyte imbalance. I agree, this is fairly unlikely. Most people (especially americans) get plenty of salt in their diet. I would think the leeching of other trace minerals would be the more present danger. Granted, as you so eloquently put it, "Some foods even have their own minerals, too." I personally eat plenty fresh fruits and vegetables. I like seafood and liver and onions. Therefore, I probably carry a fairly dense mineral load. However, I know plenty of people who live on a steady diet of chicken nuggets and other nutrient void food. These tend to be the same people who would jump all over the idea of ultra pure bottled water. I'm not saying it would instantly kill them, just make them more prone to several diseases and disorders. In the end though, if you really wanted to OD on water, you could pretty easily do it by drinking large amounts of UPW.
38. Re:Fresh water? by ceoyoyo · 2012-01-27 05:16 · Score: 1
  
  Ah, a homeopath.
39. Re:Fresh water? by ceoyoyo · 2012-01-27 05:20 · Score: 2
  
  Ah, making stuff up on Slashdot. Pure water might pull a little bit of salt from surrounding tissue. It's no big deal. It quickly becomes not-so-pure water. Any drinkable water is considerably purer than your bodily fluids and so there will be osmotic pressure.
  I've drunk multi-distilled water and it's fine. I grew up drinking ordinary distilled water because our town water was so hard, and it's fine. Except for tasting slightly different, there's no noticeable effect.
40. Re:Fresh water? by ceoyoyo · 2012-01-27 05:21 · Score: 2
  
  People don't get any significant amount of electrolytes from drinking water. So it doesn't matter the situation. Any potable water, fresh, distilled or ultra distilled, it's all the same as far as your body is concerned.
41. Re:Fresh water? by ceoyoyo · 2012-01-27 05:23 · Score: 1
  
  Oh god, the raindrops! They burn!
  You can drink pure water. It's okay.
42. Re:Fresh water? by chichilalescu · 2012-01-27 05:29 · Score: 1
  
  so (only) pure water is fine for marathons as well?
  
  --
  new sig
43. Re:Fresh water? by WillgasM · 2012-01-27 05:32 · Score: 1
  
  There are plenty of people that are mineral deficient already. A range of studies showed that somewhere between 68% and 80% of americans are deficient in one important trace mineral or another. Even if you didn't drink enough UPW to reach a state of water toxicity, you could still be exacerbating an existing problem. It might not kill you, but what about arthritis, hypertension, osteoporosis, anemia, MS, cataracts, etc?
44. Re:Fresh water? by avandesande · 2012-01-27 05:36 · Score: 1
  
  What isn't urban legend is that distilled water tastes bad.
  
  --
  love is just extroverted narcissism
45. Re:Fresh water? by WillgasM · 2012-01-27 05:44 · Score: 1
  
  you're missing something. In my area we have hard water (from ground water). It's fairly saturated in minerals and is in many ways healthier than most tap water. Even soft water has a decent mineral load. Distilled and especially UPW, however, have little to no mineral load. Not only do they not provide any minerals, but they actively strip minerals from your body. We're not talking about no minerals, we're talking negative minerals. Granted, it's still not terribly likely you'll develop a case of water intoxication. But in a world of fast food diets where most people are already mineral deficient, why would you choose to further rob your body of minerals by drinking UPW?
46. Re:Fresh water? by ArsenneLupin · 2012-01-27 05:48 · Score: 1
  
  How do you know? Nowhere did he say he thinks about men when doing this exercise...
47. Re:Fresh water? by ceoyoyo · 2012-01-27 06:02 · Score: 1
  
  During a long run like a marathon, and after shorter ones, you want to make sure you're taking in electrolytes as well as water, but drinking tap instead of distilled water is definitely NOT going to do that for you. Many runners use some kind of sports drink instead of or in addition to water, or drink water plus eating gels or bars with lots of salts in them.
  The difference between tap water and distilled is negligible in terms or electrolytes gained or lost through drinking it.
48. Re:Fresh water? by ceoyoyo · 2012-01-27 06:04 · Score: 1
  
  Aw, do you see the letters "hom" and automatically think homosexual? That's cute.
49. Re:Fresh water? by Khyber · 2012-01-27 06:16 · Score: 1
  
  The second you expose RO or deionized water to atmosphere, it starts sucking up ions. It doesn't stay super-pure more than a few minutes before it's picking crap up out of the atmosphere.
  
  --
  Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
50. Re:Fresh water? by Khyber · 2012-01-27 06:17 · Score: 1
  
  "You won't be able to drink much"
  Your ignorance says while I've been downing pure deionized and distilled water for years, with zero ill effect.
  
  --
  Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
51. Re:Fresh water? by WebSorcerer · 2012-01-27 06:19 · Score: 3, Interesting
  
  I'm a Ph.D. Chemist who has done some water purification studies. One difficulty is the build-up of particulate matter on/in the filter which slows down (eventually stops) flow through the filter.
  This problem can be addressed with the use of two filters in parallel, one of which is being back-flushed while the other operates. With the current types of filters, the system eventually plugs due to micro particulates. Perhaps this Graphine filter is immune to plugging, and merely flushing the surface will clean it.
  As you may have surmised from previous posts, it holds out the possibility of a limitless supply of potable water. What a boon to mankind!!
52. Re:Fresh water? by Chuckstar · 2012-01-27 06:29 · Score: 1
  
  You're still talking pretty small amounts of minerals. And, anyway, that's very different than claims of water intoxication. Eat an extra banana a week and you'll make up much more than all the minerals that deionized water would pull out of your body.
53. Re:Fresh water? by gmuslera · 2012-01-27 06:35 · Score: 1
  
  That it is graphene could mean that could be no "holes" where microparticulates get stuck, as in physical filters.
54. Re:Fresh water? by game+kid · 2012-01-27 06:40 · Score: 1
  
  Part of the mindblow comes from the even more intense fish smell.
  
  --
  You can hold down the "B" button for continuous firing.
55. Re:Fresh water? by V.+P.+Winterbuttocks · 2012-01-27 06:44 · Score: 2
  
  Protip: tuna is a fish. The stuff you buy in a can is not made from actual mermaids.
  
  --
  I'm the real Vorokrytin P. Winterbuttocks.
56. Re:Fresh water? by Chuckstar · 2012-01-27 07:18 · Score: 1
  
  In my last comment, I meant "ultrapure water", not just merely deionized water.
57. Re:Fresh water? by elistan · 2012-01-27 07:18 · Score: 2
  
  I'll pile on the bandwagon, but with some numbers to back up my comments. *grin*
  
  Here's a study on the NIH website comparing tap to bottled water.
  
  Dietary Reference Intakes: (similar concept to RDA)
  Calcium: 1000 mg
  Magnesium: 420 mg
  Sodium: 500 to 2400 mg
  
  Sampled tap waters on average (and std dev):
  Calcium: 37mg/L (22.4) - 3.7% of DRI
  Magnesium: 11.47 mg/L (10.64) - 2.7% of DRI
  Sodium: 44 mg/L (49) - 8.8% to 1.8% of DRI
  
  So anybody who's relying on tap water for their mineral intake needs to be drinking 11 to 55 liters per day on average. (It's hard to find numbers regarding deaths from drinking too much water, but my impression is that the above amounts could easily lead to death. Drinking tap vs mineral-free water would not a factor.) Anybody who's not getting any minerals from drinking water isn't missing out on much at all.
58. Re:Fresh water? by dave420 · 2012-01-27 07:23 · Score: 1
  
  Something just flew clear, clear over your head. It must be a lack of minerals screwing you up. I would put money on you having ingested some water recently - that's the only possible explanation.
59. Re:Fresh water? by dave420 · 2012-01-27 07:25 · Score: 1
  
  I think you are overestimating the amount of minerals in water, and severely underestimating the amount of minerals in food. Eat an extra sandwich a month, and you'll more than cover any loss of minerals from drinking distilled water.
60. Re:Fresh water? by RussellSHarris · 2012-01-27 07:29 · Score: 1
  
  It sounds like you've got it all figured out.
  I suppose I should probably blame this.
61. Re:Fresh water? by operagost · 2012-01-27 07:38 · Score: 1
  
  That's OK. You've been handling my ass pennies.
  
  --
  
  Gamingmuseum.com: Give your 3D accelerator a rest.
62. Re:Fresh water? by Baloroth · 2012-01-27 07:47 · Score: 1
  
  My point was that a person drinking distilled water would be at a disadvantage in their mineral content vs. someone drinking undistilled water. Wikipedia and the Journal of General Internal Medicine seem to agree with me. Distilled water is certainly not dangerous in any way, but we do obtain certain not insignificant amounts of minerals from tap water, which we do not from distilled water.
  
  --
  "None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
63. Re:Fresh water? by bky1701 · 2012-01-27 07:58 · Score: 1
  
  Wow, so much misinformation on slashdot on this topic it is staggering. Chemistry education must really be slacking.
  
  ANY water that is drinkable is essentially distilled. The difference between distilled and purified (and even tap, assuming not too much chlorine) is miniscule and is really only a concern in specialized situations. The problem of water intoxication only applies if you drink too much water (as in, far more than you naturally would imagine), or only drink water (which becomes more of an issue of starvation). Distilled water is not dangerous at all. You will not have "electrolyte depletion" from drinking it. If you think so, please do the world a favor and read a biology and/or chemistry textbook before spreading misinformation.
  
  --
  Great Intellect...
64. Re:Fresh water? by LeDopore · 2012-01-27 08:05 · Score: 1
  
  I'm with you on this one, Russ1642.
  
  --
  Expected time to finish is 1 hour and 60 minutes.
65. Re:Fresh water? by BitZtream · 2012-01-27 08:57 · Score: 1
  
  The amount of salt you would gather wouldn't make it worth the effort to bother collecting it when there are essentially limitless supplies (for our needs anyway) already laying all over the place on the ground or just under the surface. Hell, the entire world uses basically one mine anyway, and its not like its the only one.
  We're not going to be using 'new' sources of salt anytime soon, all they do now is pick it up with bulldozers and dump it in a truck, its just like picking up dirt, except they essentially pick up bulldozers/dumptrucks full of it for just the cost of running the bulldozer/dump trucks
  
  --
  Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
66. Re:Fresh water? by roman_mir · 2012-01-27 09:43 · Score: 1
  
  I've been drinking distilled water almost exclusively for near 12 years. You are wrong.
  
  --
  You can't handle the truth.
67. Re:Fresh water? by Fned · 2012-01-27 09:53 · Score: 1
  
  whoooooosh*SPLAT*
68. Re:Fresh water? by Fned · 2012-01-27 09:55 · Score: 1
  
  Weird how people can taste the difference...
69. Re:Fresh water? by tomhath · 2012-01-27 11:30 · Score: 1
  
  No, because in order to get through it the water has to evaporate. And if you're going to evaporate the water then just distill it, you don't need this stuff to desalinate water. Conventional distillation works fine.
70. Re:Fresh water? by thegarbz · 2012-01-27 12:05 · Score: 1
  
  My mother swears she can taste a difference in water that runs over a rock on the way into the glass. This may have applied for the first few days she owned the rock, but not 7 years later.
  Like high end audio cables I wonder how this stands up to a double blind test.
71. Re:Fresh water? by tbird81 · 2012-01-27 14:10 · Score: 1
  
  Yep. In fact every day a cup or two of water is created by our bodies in the metabolism of our food. (e.g. C6H12O6 [glucose] + 6O2 = 6CO2 + 6H2O + Energy)
72. Re:Fresh water? by tbird81 · 2012-01-27 14:16 · Score: 1
  
  Check again.
73. Re:Fresh water? by tibit · 2012-01-28 17:20 · Score: 1
  
  There's no way, I don't think, to have liquid water with things merely dissolved in it and it being ever sufficient nutritionally. So even if you got water saturated with whatever you can saturate it, it wouldn't help you. So this whole idea is just silly. You need to be taking in some solids, or at least emulsions (breast milk, duh).
  Saying that something is "healthier" because it's got some minerals dissolved in it is just repeating marketing speak. It means zilch. It's what the marketing departments the world over want you to believe, but it's pure, unadulterated fantasy.
  So, let's repeat: if you had only water with dissolved stuff to drink, you'd die probably within a couple months at best. Just check what human nutritional needs are, and how much of that stuff is water soluble (and what the solubilities are!). Let's be clear: I'm talking about a solution, perhaps even a saturated one, but not about an emulsion, and that IIRC implies that using soap-like action to smuggle lipids is out of question, as I don't think that soap in water is technically a solution anymore -- someone please correct me if I'm wrong, though.
  This being out of the way, it's only sane to assume we're getting most of the nutrients via solid foods, and those contain really the minerals that we need. The water can be completely pure. It won't strip you from anything, because as soon as it mixes with solid foods being digested in your stomach, it becomes loaded chock full of those minerals that it just leeched out from the food, not from your freakin' body for crying out loud. The body won't be getting a chance to truly get rid of any minerals in the net -- whatever it loses gets quite promptly replaced.
  So please, stop with the silliness of it all, because this whole "stripping minerals from your body" by drinking pure water is a notion that's completely meaningless in real life. It would only be meaningful if you drank that water and had nothing else to eat or drink, and I think we're both satisfied that this is no good no matter what's dissolved in the water.
  Water intoxication has nothing to do with minerals, it's about electrolytic imbalance -- you pee out sodium and potassium, and since peeing is the only way you'll get rid of the water (short of having diarrhea or puking it out), you will eventually run out, usually first of sodium. And that will be lethal.
  
  --
  A successful API design takes a mixture of software design and pedagogy.
74. Re:Fresh water? by tibit · 2012-01-28 17:27 · Score: 1
  
  In general, you don't get sufficient trace minerals from water unless you select your drinking water to be rich in them all, and that's not that trivial. If you go to a random "mineral" water source, even with pretty "full" taste, you'll find it's probably loaded with a couple minerals and whatever else is there is most likely insufficient anyway. You need solid foods, end of story. Cataracts are not due to mineral deficiencies, they are due to denaturation of lens protein. UV exposure and ionizing radiation will do that to you; airline pilots get them more often than general population, for example.
  Are you trying to replace Dr. Bob?
  
  --
  A successful API design takes a mixture of software design and pedagogy.
75. Re:Fresh water? by tibit · 2012-01-28 17:31 · Score: 1
  
  As far as electrolytic balance goes, usually if you can't taste it, it's not there. Minerals != electrolytes. Crazy tasty mineral water won't help you in a marathon, you need to add sodium and potassium to the water. As far as bioavailable sodium and potassium is concerned, mineral waters, tap water, and ultrapure spectroscopy-grade water are all equally bad.
  
  --
  A successful API design takes a mixture of software design and pedagogy.
76. Re:Fresh water? by tibit · 2012-01-28 17:32 · Score: 1
  
  Those amounts are completely insignificant since whatever is concentrated in the solid foods that you eat will completely overwhelm whatever is in the water. The animals and plants that you eat have already done all the mineral picking for you, your water can be pure.
  
  --
  A successful API design takes a mixture of software design and pedagogy.
77. Re:Fresh water? by Tsingi · 2012-01-29 01:00 · Score: 1
  
  I can't tell if you're a troll or just simple.
  After the first sentence, I didn't read it either.
78. Re:Fresh water? by iggymanz · 2012-01-29 16:50 · Score: 1
  
  people have killed themselves in exactly that manner by drinking excessive amounts of tap water; it doesn't have to be distilled water.
wonder substance by tverbeek · 2012-01-27 03:25 · Score: 2

But can it be used as a dessert topping?

--
http://alternatives.rzero.com/
1. Re:wonder substance by Bill+Hayden · 2012-01-27 03:33 · Score: 4, Funny
  
  No, just as a floor wax at this point.
  
  --
  Protect your browser with the Force Safe Search add-on
2. Re:wonder substance by osu-neko · 2012-01-27 04:30 · Score: 1
  
  But can it be used as a dessert topping?
  It's probably delicious, and cures cancer too. Seriously, this substance is getting ridiculous... what miraculous property will be discovered next?
  
  --
  "Convictions are more dangerous enemies of truth than lies."
3. Re:wonder substance by del_diablo · 2012-01-27 05:00 · Score: 1
  
  It wouldn't surprise me if it did.
  Asbestos was a godsend back in its day. Solid, easy to use, fireproff, etc. Turns out that if you breathed it, it stuck and behaved like glass shards.
4. Re:wonder substance by FatLittleMonkey · 2012-01-27 18:38 · Score: 1
  
  Asbestos was, after all, a wonder substance in its day.
  
  --
  Science is all about firing a drunk pig out of a cannon just to see what happens.
Important detail by zAPPzAPP · 2012-01-27 03:25 · 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?
1. Re:Important detail by Suigintou · 2012-01-27 04:37 · Score: 1
  
  In the PDF they say that if the filter gets too hot it becomes impermeable to water. So I guess if the steam is too hot it wouldn't work. On the other hand, if you just let any aqueous solution sit for a while in a container sealed with the filter on top, you get a stronger solution over time. They say they tried it with booze and yes, it works. Useful if your end product will evaporate quicker than water.
2. Re:Important detail by Joce640k · 2012-01-27 04:41 · Score: 1
  
  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.
  It says they sealed some water containers with graphene and the water evaporated as if the graphene wasn't there. They didn't heat/boil the tubes, they just let them stand for several days.
  It doesn't say what happens if you pour water on it. It might drip...maybe they're waiting for more funding so they can perform such a complex experiment.
  
  --
  No sig today...
graphene oxide, not graphene by THE_WELL_HUNG_OYSTER · 2012-01-27 03:28 · Score: 5, Informative

The material they used was NOT graphene. It was graphene oxide.
1. Re:graphene oxide, not graphene by Sulphur · 2012-01-27 03:51 · Score: 1
  
  The material they used was NOT graphene. It was graphene oxide.
  Graphene monoxide or graphene dioxide?
2. Re:graphene oxide, not graphene by Anonymous Coward · 2012-01-27 04:13 · Score: 1
  
  That's okay, the substance it filtered was dihydrogen monoxide.
3. Re:graphene oxide, not graphene by Dishevel · 2012-01-27 04:31 · Score: 1
  
  That's okay, the substance it filtered was dihydrogen monoxide.
  that shit is DEADLY.
  
  --
  Why is it so hard to only have politicians for a few years, then have them go away?
4. Re:graphene oxide, not graphene by 19thNervousBreakdown · 2012-01-27 04:51 · Score: 1
  
  Breathing just one lungful will kill you.
  
  --
  <xml><I><am><so><damn>Web 2.0</damn></so></am></I></xml>
5. Re:graphene oxide, not graphene by sexconker · 2012-01-27 05:31 · Score: 2
  
  The material they used was NOT graphene. It was graphene oxide.
  Graphene monoxide or graphene dioxide?
  Graphene trioxide. Turbo. Power.
  For the closest chave a man can get.
6. Re:graphene oxide, not graphene by holmstar · 2012-01-27 07:06 · Score: 1
  
  Obligatory: Fuck Everything, We're Doing Five Blades
7. Re:graphene oxide, not graphene by Xiterion · 2012-01-27 08:36 · Score: 1
  
  Neither, actually. According to the article:
  
  Graphene oxide is the same graphene sheet but it is randomly covered with other molecules such as hydroxyl groups OH-.
  So it's apparently not a simple oxide in the sense of carbon dioxide, etc. It's more graphene with some oxygens added in various configurations.
8. Re:graphene oxide, not graphene by FatLittleMonkey · 2012-01-27 18:40 · Score: 1
  
  By drowning.
  
  --
  Science is all about firing a drunk pig out of a cannon just to see what happens.
Journalist != scientist by tomhath · 2012-01-27 03:30 · Score: 3, Interesting

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.
1. Re:Journalist != scientist by msheekhah · 2012-01-27 04:13 · Score: 1
  
  But this doesn't help us with desalination unless we do something like have a solar collector to cause evaporation... not nearly as cool or useful as if it could be used as a filter
  
  --
  Mark Anthony Collins
2. Re:Journalist != scientist by Khyber · 2012-01-27 06:20 · Score: 1
  
  "But this doesn't help us with desalination unless we do something like have a solar collector to cause evaporation"
  Hi, my name is sublimation. I come from your high school chemistry years and would like a word with you.........
  
  --
  Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
3. Re:Journalist != scientist by treeves · 2012-01-27 10:37 · Score: 1
  
  Sublimation is going from solid straight to gas. Like when the old ice cubes in your freezer ice trays shrink after months.
  Evaporation is all that is needed here.
  
  --
  ...the future crusty old bastards are already drinking the Kool-Aid.
4. Re:Journalist != scientist by Khyber · 2012-01-27 11:29 · Score: 1
  
  ....you don't know sea ice can sublimate? *shakes head*
  
  --
  Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
5. Re:Journalist != scientist by treeves · 2012-01-28 16:11 · Score: 1
  
  That's what your going to do to desalinate water? Let sea ice sublimate (and collect the vapor and condense it)?
  Good luck with that.
  
  --
  ...the future crusty old bastards are already drinking the Kool-Aid.
Re:Geomembrane by TheLink · 2012-01-27 03:30 · Score: 2

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?
--
- Too many replies beneath your current threshold
Welcome to the Diamond Age by Magada · 2012-01-27 03:32 · Score: 1

that is all

--
Something bad is coming when people are suddenly anxious to tell the truth.
Graphene Condom? by swb · 2012-01-27 03:35 · Score: 4, Funny

Lets all the delicious moisture through, blocks the stuff you want blocked???
Ethanol by troylanes · 2012-01-27 03:40 · Score: 1

Super still anybody :) ? I can see it now: BATF busts graphene lab in remote Kentucky hills. Moonshine operation shutdown.
1. Re:Ethanol by michael_cain · 2012-01-27 04:27 · Score: 1
  
  There are a variety of organic molecules that can be produced by fermentation (ethanol, butanol, etc) suitable for use as liquid fuels, that would be enormously more practical if the distillation process could be made more efficient. When the goal is water removal, this type of filter should be able to make industrial-scale vacuum distillation much simpler.
Does it erase the Water Memory? by Belladora · 2012-01-27 03:44 · Score: 2, Funny

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...
1. Re:Does it erase the Water Memory? by Tassidus · 2012-01-27 03:50 · Score: 2
  
  Seems a bit weird to respond to a scientific discussion, with scientific proof and evidence, with an article that says "No scientific evidence supports this claim". It's equivalent to sitting in an evolution debate and proposing the idea of creationism. :-p
2. Re:Does it erase the Water Memory? by Pope · 2012-01-27 04:06 · Score: 1
  
  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...
  Are you clinically retarded?
  
  --
  It doesn't mean much now, it's built for the future.
3. Re:Does it erase the Water Memory? by semi-extrinsic · 2012-01-27 04:33 · Score: 1
  
  I'm 90% sure that a *wooosh* is in order. 10% chance GP is just nuts.
  
  --
  for i in `facebook friends "=bday" 2>/dev/null | cut -d " " -f 3-`; do facebook wallpost $i "Happy birthday!"; done
4. Re:Does it erase the Water Memory? by Dishevel · 2012-01-27 04:34 · Score: 1
  
  Water has no memory. You are being lied to so people can make money off you.
  If you want cheap homeopathic results just drink tap water and believe it is fixing you.
  With the proper belief you will get the benefit of the placebo effect without paying extra and as a bonus you can believe that the water is doing a whole host of killer things for you.
  
  --
  Why is it so hard to only have politicians for a few years, then have them go away?
5. Re:Does it erase the Water Memory? by Baloroth · 2012-01-27 04:48 · Score: 1
  
  Are you deaf from the "WHOOOOSH"?
  
  --
  "None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
6. Re:Does it erase the Water Memory? by EnsilZah · 2012-01-27 05:00 · Score: 2
  
  I believe the Whooosh failed to permeate the membrane.
7. Re:Does it erase the Water Memory? by ibutsu · 2012-01-27 06:31 · Score: 1
  
  Actually tap water is probably *more* effective, especially when you take into account the various prescription drugs that have been dumped into the water supply!
8. Re:Does it erase the Water Memory? by FatLittleMonkey · 2012-01-27 18:59 · Score: 1
  
  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...
  Indeed. This may finally give homeopaths a weapon against the dread pirate Refillers.
  (Refillers propagate the notion that, to be consistent with their beliefs, homeopathy users need only ever buy one sample of each preparation. Consume 90%, refill from the tap, shake to activate, and you have an as-new bottle of magic water. In perpetuity. Even more potent than the original. Make bottles to give away to friends and neighbours for free.)
  
  --
  Science is all about firing a drunk pig out of a cannon just to see what happens.
If it blocks Helium by DickBreath · 2012-01-27 03:50 · 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.

--

I'll see your senator, and I'll raise you two judges.
1. Re:If it blocks Helium by Onymous+Coward · 2012-01-27 07:18 · Score: 1
  
  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 enjoyed reading that as if the world's economy were based on birthday balloon bouquets.
  But wouldn't we suffer an economic collapse if everyone reused balloons from prior years?!
Re:Geomembrane by Anonymous Coward · 2012-01-27 03:53 · Score: 1

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.
Or it could be replaced less often.
More amazing uses for the miracle substance by cvtan · 2012-01-27 03:53 · Score: 1

So if people can make exotic materials like graphene, why can't my doctor make my low back pain go away?

--
Sorry, but gray text on gray background is making my eyes bleed.
1. Re:More amazing uses for the miracle substance by felipekk · 2012-01-27 03:59 · Score: 1
  
  Same reason for both: money.
2. Re:More amazing uses for the miracle substance by tbird81 · 2012-01-27 14:24 · Score: 1
  
  Yes, they do. Along with weight-loss, gentle exercise, and keeping on with your day. But that's not what people want.
  Chronic back painers are a terrible breed of people. They smoke, they're fat, and they're stupid. They'll walk into the practice with their hand on their back, and want the doctor to sign a medical certificate.
  Yellow flags for back pain:
  A negative attitude that back pain is harmful or potentially severely disabling
  Fear avoidance behaviour and reduced activity levels
  An expectation that passive, rather than active, treatment will be beneficial
  A tendency to depression, low morale, and social withdrawal
  Social or financial problems
3. Re:More amazing uses for the miracle substance by FatLittleMonkey · 2012-01-27 19:01 · Score: 1
  
  Try heroin mixed with a mild laxative.
  
  --
  Science is all about firing a drunk pig out of a cannon just to see what happens.
Meh. by PPH · 2012-01-27 04:06 · Score: 1

My kids' diapers.

--
Have gnu, will travel.
Negative pressure at atomistic scale ? by advid.net · 2012-01-27 04:09 · Score: 1

Last pdf page:

The fact that the water fills the 2D channel even under a negative pressure in the left reservoir indicates [...]
I understand that sometime negative pressure means lower pressure than global/ambiant pressure.
But here in this 2D atomistic simulation I don't know what they mean.
1. Re:Negative pressure at atomistic scale ? by sveinb · 2012-01-27 12:28 · Score: 1
  
  I didn't read the article yet, but in general a negative pressure in a liquid means that you're trying to pull it apart with external forces, a bit like a solid under tension. Usually an unstable situation, since a cavitation bubble would be energetically favorable.
2. Re:Negative pressure at atomistic scale ? by advid.net · 2012-01-28 03:00 · Score: 1
  
  You can't pull a liquid on macroscopic scale (thus the maximum dwell pump height, dependent on external pressure).
  But on millimetric scale (and bellow) the surface tension can let you pull a small amount of liquid.
  Maybe this is the answer.
Stillsuits!! by BigBong · 2012-01-27 04:27 · Score: 1

Now we have the perfect material with which to make stillsuits! Frank Herbert would shed a tear if he were alive.
1. Re:Stillsuits!! by EnsilZah · 2012-01-27 05:02 · Score: 1
  
  He's probably spit in the researchers' faces!
application to bootlegging by anwyn · 2012-01-27 04:45 · Score: 1

If this process were used in bootlegging, it would eliminate the still's heat signature. It would eliminate the still's distinctive sound. It might make it economical for many people to have their home stills in their garages. I see governmental regulation soon.
1. Re:application to bootlegging by Spykk · 2012-01-27 05:30 · Score: 1
  
  You can always just use freeze distillation if you want to distill spirits in your kitchen. It isn't as efficient as a traditional still and it doesn't remove the fusels but freezing some of the water out of hard cider is pretty simple.
Might have to do with atomic forces? by JSBiff · 2012-01-27 04:45 · Score: 1

I don't really know, but I'd suspect that it has something to do with like,electrical charge or something, not size - e.g. they're both small enough to fit through, but the helium experiences some sort of repulsive force which the water does not as it passes through the field created by the graphene.
1. Re:Might have to do with atomic forces? by geekoid · 2012-01-27 12:51 · Score: 2
  
  If only they had an article you cold read that tells you how it works.
  
  --
  The Kruger Dunning explains most post on /. http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
2. Re:Might have to do with atomic forces? by tbird81 · 2012-01-27 13:59 · Score: 2
  
  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!
3. Re:Might have to do with atomic forces? by FiloEleven · 2012-01-28 02:01 · Score: 1
  
  Cold reading is a skill that takes a lot of practice to get right; it shouldn't be surprising that a lot of information is missed by those who haven't quite got the hang of it yet.
  
  --
  Your brain is not a computer.
Re:At last no more Fluoride ! by Anonymous Coward · 2012-01-27 04:46 · Score: 1

Chlorine prevents pathogens from setting up shop in your tap water. Fluoride keeps your teeth from falling out. They wouldn't spend $$$ putting additives in the water if they didn't have a good reason. Besides, last I checked, the bigwigs in DC drink the same water.
Re:Graphene condoms? by Joce640k · 2012-01-27 04:49 · Score: 1

Graphene is one of the stiffest known materials.
Unrolling a graphene condom might be a problem but once it's on there you won't need Viagara.

--
No sig today...
What about cooling? by ScaledLizard · 2012-01-27 04:54 · Score: 1

Is this useful for cooling my superfast graphene processors?
BBC says booze by Dave+Whiteside · 2012-01-27 04:56 · Score: 1

http://www.bbc.co.uk/news/science-environment-16747208 - at least the beeb has a better use - ... Miracle material graphene can distil booze, says study

--
who where what when now?
"Water poisoning" by sgunhouse · 2012-01-27 05:00 · Score: 1

Exactly ...
I recall a warning I saw last year about giving infants water instead of formula - especially purified water. They referred to it as water poisoning (which would seem to me a misleading term, but I don't get to choose these things).
So it is a valid consideration for those who never eat food ...
1. Re:"Water poisoning" by tibit · 2012-01-28 17:22 · Score: 1
  
  Purified water is pretty much same as tap water as far as very young infants are concerned: it will give them electrolyte imbalance, and that will kill an infant much faster than it'd kill an adult. Purified water and tap water are equivalently devoid of sodium and potassium, and that's what counts, not some nebulous minerals that give water a pleasant taste and are omnipresent in marketing (supposed health benefits, my ass).
  
  --
  A successful API design takes a mixture of software design and pedagogy.
Re:Wait, what about pressure? by amRadioHed · 2012-01-27 05:01 · Score: 2

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
Hydrogen by sycodon · 2012-01-27 05:40 · Score: 2

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.
1. Re:Hydrogen by Patch86 · 2012-01-27 07:14 · Score: 3, Informative
  
  According to TFA (well, the BBC article on the same subject, anyway) it blocks helium molecules with what appears to be 100% efficiency. Helium molecules are smaller than the molecules in a standing mass of hydrogen, since hydrogen atoms bond together to form H2.
Helium by TuringCheck · 2012-01-27 05:47 · 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.
1. Re:Helium by tibit · 2012-01-27 10:25 · Score: 1
  
  Second that. Helium will happily go through glass, even inch thick glass.
  
  --
  A successful API design takes a mixture of software design and pedagogy.
Practical Joke by Gideon+Wells · 2012-01-27 06:30 · Score: 1

I swear, if I didn't know better I'd be willing to call graphene an elaborate prank at this point. Groups of scientists trying to one up each other over what this thing can do. Two months before it can transmute gold? :P

--
by Anonymous Coward: I, for one, welcome the shift from car analogies to pizza analogies. um.. overlords?
MOONSHINE!!! by dirtydog · 2012-01-27 06:33 · Score: 1

I can see the next Discovery Channel Moonshiners show now:
Tickle!!! Get the graphene filter ready for this mash!!!
water intoxication, by tap or ultrapure by Onymous+Coward · 2012-01-27 06:56 · Score: 2

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.
same atom, really? by Onymous+Coward · 2012-01-27 07:10 · Score: 2

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.
1. Re:same atom, really? by Tsingi · 2012-01-27 07:20 · Score: 1
  
  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.
  You certainly could look at it that way. IANAP (Physicist) but I think that electrons swap out fairly frequently. Don't we take advantage of that and call it electricity?
  So, to qualify further, excepting electrons, which are all over the map, the nuclei of those atoms should be fairly old. I think it takes a bit more persuasion to shake those up.
  Anyway, at the end of the day, all the water molecules are fairly new, even if you discount the fickle nature of electrons.
2. Re:same atom, really? by Fned · 2012-01-27 09:51 · Score: 1
  
  This is my family's atom. It was my father's, and his father's before him, and his father's father's father's before him.
  Through the years the electron's been replaced three times and the proton twice, but it's still the same atom.
3. Re:same atom, really? by tibit · 2012-01-28 16:59 · Score: 1
  
  Free electrons are exactly equivalent, talking about getting a "different" electron is meaningless. That's the problem you get with the quantum world: common sense terms simply don't apply to it in certain cases. Just because you can conjure up some adjective and stick it to an electron doesn't have to mean anything.
  There's no way, in general, experimentally, to "mark" electrons to figure out if at some later time someone hands you those electrons back, you're still looking at same ones or not. Same applies to atoms in ground energy states: there's no way to mark them. Heck, this applies to molecules, too. Standard disclaimer: someone more clued in please chime in if I'm talking BS.
  
  --
  A successful API design takes a mixture of software design and pedagogy.
Manifacturing by ironman_one · 2012-01-27 07:10 · Score: 1

Well this is all nice and fine but.. Garphene is just one atom thick. Can you actualy prodeuce any larger quamtity today for filters or is it to brittle for any application outside a lab?
Re:Preach vodka by P-niiice · 2012-01-27 08:45 · Score: 1

My thoughts exactly. Cheap filters that could be rinsed off and reused forever. Run a little water through them, and you have clean water, fast.
Re:Wait, what about pressure? by _0xd0ad · 2012-01-27 09:06 · Score: 1

They wouldn't use a bottle. They'd just need a way for the container to adapt to the amount of liquid in it at any given point in time.
Suppose they have a vertical-walled beaker of vodka with a sheet of graphene exactly the same size as the inside of the beaker. Ethanol evaporation is directly proportional to the un-protected surface area (negligible); water evaporation is directly proportional to the entire surface area, since water would evaporate perfectly well through the membrane.
As the water evaporates, the level of the liquid drops, and the floating graphene membrane drops along with it.
Of course, the slightest air current would probably pile up the graphene membrane on one side of the beaker, so you'd probably have to come up with something a little more elaborate than that, but you get the point.
It's already the subject of further research by Mick+R · 2012-01-27 10:26 · Score: 1

using the World Community Grid virtual super computer. www.worldcommunitygrid.org
No, the water isn't passing through. by lvxferre · 2012-01-27 16:50 · Score: 1

I think I have the solution for 'why water can pass through but helium [smaller] not': the water is not passing through at all. It's graphene hydroxide/oxide, after all... the hydroxyl radical from the membrane steals a H 'cation' from a water molecule, an electron from graphene proper and deattaches itself, forming a new molecule. The 'old' water molecule, now a OH radical, attaches itself at the graphene yielding an electron in the way.

The thing is, the 'new' molecule has 50% odds of being at any side of the graphene layer. If you have lots of water in one side but none in the other, it'll looks like the water is passing through.

This would explain why helium cannot pass - it's smaller than a water molecule, but far, FAR BIGGER than a H (H = a proton alone). The OH radical attached to the membrane can rearrange itself to either side of the membrane easily, since it's bonded to the layer, allowing the process to continue.

TL; DR: The water isn't passing through, it's being broken and recombined at the other side.

--
Nerdy news for your nerdy needs? http://www.soylentnews.org Soylent News is people!
Blocking Helium but letting H2O to pass through? by Taco+Cowboy · 2012-01-28 00:19 · Score: 1

Please pardon my stupidity, but isn't the size of H2O molecule larger than that of Helium?

--
Muchas Gracias, Señor Edward Snowden !