Making Salt Water Drinkable Just Got 99 Percent Easier
Access to steady supplies of clean water is getting more and more difficult in the developing world, especially as demand skyrockets. In response, many countries have turned to the sea for potable fluids but existing reverse osmosis plants rely on complicated processes that are expensive and energy-intensive to operate. Good thing, engineers at Lockheed Martin have just announced a newly-developed salt filter that could reduce desalinization energy costs by 99 percent.
The Reverse Osmosis process works on a simple principle: molecules within a liquid will flow across a semipermeable membrane from areas of higher concentration to lower until both sides reach an equilibrium. But that same membrane can act as a filter for large molecules and ions if outside pressure is applied to one side of the system. For desalinization, the process typically employs a sheet of thin-film composite (TFC) membrane which is made from an active thin-film layer of polyimide stacked on a porous layer of polysulfone. The problem with these membranes is that their thickness requires the presence of large amounts of pressure (and energy) to press water through them.
Lockheed Martin's Perforene, on the other hand, is made from single atom-thick sheets of graphene. Because the sheets are so thin, water flows through them far more easily than through a conventional TFC. Filters made through the Perforene process would incorporate filtering holes just 100 nm in diameter—large enough to let water molecules through but small enough to capture dissolved salts. It looks a bit like chicken wire when viewed under a microscope, John Stetson, the Lockheed engineer credited with its invention, told Reuters. But ounce for ounce, its 1000 times stronger than steel.
"It's 500 times thinner than the best filter on the market today and a thousand times stronger," Stetson explained to Reuters. "The energy that's required and the pressure that's required to filter salt is approximately 100 times less."
Lockheed is reportedly already ramping up production efforts for the filters—and trying to find a way to keep them from tearing—though there are no announced plans on when they'd hit the market. Tomorrow isn't soon enough. [Reuters via MetaFilter - Wikipedia - Image: Shutterstock/Lightspring]
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FIGJAMAndrew Tarantola3/15/13 8:52pmDid the graphene industry just get a new publicist? I'd swear this is the 3rd story I've ready about graphene in the last 2 days.Reply
DanielkuntzFIGJAM3/15/13 8:59pmIt's fucking graphene. That shit is magic.Reply
DrunkenMessiahFIGJAM3/15/13 9:05pmGet used to it.You will be hearing about it A LOT more in the coming years. Graphene and it's variants (bucky balls, carbon nanotubes) are going to lead to a technological revolution that hasn't been seen since the advent of cheap steel. Cheap steel changed everything. Cars, sky-scrapers, oil drilling; all where suddenly possible thanks to cheap steel. Cheap graphene is going to make at least as big of a change. Probably bigger. Space elevators, sky-scrapers that reach miles into the air, computers with unimaginable durability and computing power. The impact will be HUGE. Humanity will never be the same. It will be our first major step to mastering the forces of nature.Its gonna be awesome!Reply- FIGJAMDrunkenMessiah3/15/13 9:10pmWell I'm glad the Roswell UFO finally gave us something besides computer chips and velcro.Reply
- DrunkenMessiahFIGJAM3/15/13 9:26pmLOL!Some aspects of graphene tech are so amazing that it really does seem like alien technology sometimes.Reply
Frankenbike666Andrew Tarantola3/16/13 6:54pmI'm starting to think that graphene in some form (graphene sheets, carbon nanotubes and bucky balls) is going to be the solution to everything. Super strong materials, filters, energy storage (supercapacitors replacing batteries), and it wouldn't surprise me if they figure in the next generation of superconductors. If we could just figure out a cheap way to make it out of the CO2 in the air, we might solve multiple problems at once.Reply
Joz JonlinFrankenbike6663/17/13 4:56pmHere's an old Ars Technica bit on graphene and supercoducting. I agree with you that graphene seems to be the answer to just about every high tech question right now. Hey, we need a space elevator. Fine, let's braid strands of graphene together to create the cable. Seriously, if you name a high tech need, there's probably an area where graphene might eventually come into play. I'm just waiting for them to figure out biotech uses for graphene, like bionic limbs, eyes, and even brain implant/interfaces. The future's so bright we'll have to wear graphene shades.http://arstechnica.com/science/2012/01/graphene-may-exhibit-exotic-superconductivity/Reply
Maxawe SomeFrankenbike6663/18/13 2:47amSo why aren't they using graphene in the real world , is it too expensive ?Reply- Frankenbike666Maxawe Some3/18/13 9:10pmBecause up until now, it's been very hard to make precisely, in large quantities. Some technologies have to wait until the tools are up to the job. You couldn't build a modern gas turbine engine in 1785, even if you had blueprints and a guide to bootstrapping modern metalurgy. It takes the combined works of a large scale civilization. We're only now learning how to make things consistently at very small scales.Reply
- Frankenbike666Joz Jonlin3/18/13 9:17pmI guaranty that graphene will somehow figure in medical nanomachines. I'm putting money on the betting pool that accidental carbon nanotubes from cigarette ash, were the cause of lung cancer all along.Carbon is about the most abundant solid material in the universe, and it looks like it's going to figure heavily in being the most useful.What makes graphene in its various forms so useful in chemistry, is that it seems like everything likes to combine with carbon. You can use it as an atomic latticework to build molecular machines.Reply
KaostheoryAndrew Tarantola3/15/13 8:12pmHow do they keep from clogging?Reply
ShadowboxinKaostheory3/15/13 8:15pmCus it's fucking graphene. That shit is magicReply
SkywalkerKaostheory3/15/13 8:18pm@shadow.. You sure?...well ... It must clog...as it stops the impurities... isn't it?...IDK but...It might as well be simpler to clean it off after use... or... Just buy a new one...they said, it will cost 99% less ... Didn't they?... :)Reply- DanielkuntzKaostheory3/15/13 9:03pmMagicReply
andinatorKaostheory3/15/13 9:10pmProbably similar to other filters, a "backwash" cycle where the impurities are rinsed off the surface and returned to the source.Reply
- GOU_NoMoreMrNiceGuy_v2Andrew Tarantola3/16/13 4:01amwhenever i watch survivorman or similar shows and they demonstrate the solar evaporation still where a plastic sheet and a cup is used to make drinking water, i'm always prompted to ask - wtf? why is potable still a problem anywhere in the world?almost everywhere you have access to sea water, you have access to the sun. and even with extremely primitive materials, people could make large solar stills.so what gives? why aren't there just gigantic solar stills making fresh water for the poor people who need it?Reply
mwlphelpsGOU_NoMoreMrNiceGuy_v23/16/13 9:42amWhat they don't show on TV is that it takes all day to make a half a cup of fresh water with a solar still. Hardly efficient enough for any wide use.Reply
wagnerrpGOU_NoMoreMrNiceGuy_v23/16/13 2:05pmIt's all a question of volume. That primitive solar still will work for emergencies to keep you alive, but it's not enough for a human to live on. You need water for coolant, sanitation, and irrigation too. You need absolutely huge tracks of land, and equally huge structures, to provide enough volume for a small village, much less a major city.Reply
cameron007mwlphelps3/16/13 3:06pmA 3' solar still in hot weather can easily produce 2+ liters per day. More than enough for a couple people to survive on. The problem is that it cannot be scaled up or the final product transported easily.This tech is more applicable to ships or large scale systems. I would also make an assumption that it is a great filtering system compared to conventional RO sources which waste a lot of water.Reply
Darth Sethiuswagnerrp3/16/13 7:12pmBut I don't want any tracks of land...I'd rather...rather...sing!Sorry, couldn't resist when I read you "tracks of land" comment.Reply
- UndergroundScientistAndrew Tarantola3/15/13 11:15pmThis is not new. Researchers knew that this would work for some time but couldn't figure out how to effectively make large graphene sheets (a problem that sounds like it hasn't been fixed).Reply
TransfixedUndergroundScientist3/15/13 11:56pmThere's a difference between "knew this would work for some time", and "actually producing the product for development and manufacture."Theory < PracticeReply
OpenSourceDWORDTransfixed3/16/13 4:51amAnd where in the article does it say "actually producing the product for development and manufacture."?The only reference I see to a physical product is:"Lockheed is reportedly already ramping up production efforts for the filters—and trying to find a way to keep them from tearing"That's a long cry from practice my friend.Theory > PropagandaReply- TransfixedOpenSourceDWORD3/19/13 1:43pmLolwut? What kind of splitting hairs is that? "Ramping up production efforts" is pretty damn close to "actually producing the product". Plus, they straight-up announced it to the world, which a company as savvy as Lockheed-Martin wouldn't do unless they were actually making the thing. Either way, saying something is theoretically possible is not anywhere close to actually producing said thing.Reply
- OpenSourceDWORDTransfixed3/19/13 5:10pm"—and trying to find a way to keep them from tearing—though there are no announced plans on when they'd hit the market." Considering the high price of graphene, this sounds like a pretty big issue to solve before pumping volumes of the material out of an assembly line. "Ramping up production efforts" could mean anything - including making enough of the material for material testing. I'm sticking to my position. Sounds great. Wake me up when "ramping up production" turns into "put into application".Reply
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