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New Process For Nanoscale Filtration Holds Promise of Cheap, Clean Water
New submitter Spinnakker writes "Lockheed Martin, traditionally known for its development of military systems and aircraft, has developed a process for perforating graphene (carbon sheets only one atom thick) that could potentially reduce the energy required for desalination by two orders of magnitude. The process tailors the hole size to the molecules being separated. In the case of desalination, one would create holes in the graphene large enough to allow water to pass but small enough to block the salt molecules. The advantage to using graphene comes from how extremely thin the material is compared to traditional filters. The thinner the filter, the less energy is required to facilitate reverse osmosis."
I remember when this theoretical technology was proposed about a year ago, and figured it would be a decade before they could actually do it.
Cheap desalinization and filtration would mean an end to one of the biggest world health problems(safe drinking water), and could improve world-wide standards of living dramatically.
How soon before I can pee into a Mr. Coffee and get iced tea?
captcha: profound
so that means each hole will be permanently gummed up with a single molecule? how many molecules of salt (etc) are there in a liter of water? how many holes? and how expensive are these graphene filters?
I thought part of the problem with current desalination techniques was that it removed all of the salts making us have to go back and re-add a bunch of phosphates and whatnot that are found in fresh water sources and are somewhat expected/required by our and plant's biological functions. That is, we were making the water too pure to be used without additional processing. This sounds like that taken the next level, so how much more efficient can it really be if the process requires even more post-processing to make it usable?
Very similar article was published half a year ago. Is there something new now?
Considering that the theoretical minimal energy requirement for seawater desalination is approx. 0.75 kWh/m3 and current RO technology can be as low as 1.5 to 2 kWh/m3 (+ an other 2 kWh/m3 to pretreat the seawater) then I am really wondering how they will gain two orders of magnitude less energy? Can anybody enlighten us about that?
[quote]Lockheed officials see other applications for Perforene as well, from dialysis in healthcare to cleaning chemicals from the water used in hydraulic fracturing, or "fracking," of oil and gas wells[/quote]
This does sound like a miracle discovery. In theory you could filter out poisons and microbes from brackish wells as well.
If this turns out to be as good as it sounds, the financial and social impacts will be staggering.
I had an under-the-sink reverse osmosis system (Ametek, no longer in business) more than 20 years ago. I bought it for some of the plants I was growing at the time (insectivores, epiphytes, etc.), but then I discovered that *I* liked the taste of pure water myself and my usage doubled. Those damned RO membrane cartridges were quite expensive, and I eventually stopped using it. It would be nice to see the technique revamped with graphene if it can lower the cost in general (since home RO never used electricity anyway).
So the company that made the F-22, and currently makes the F-35, has just become one of the greenest companies on the planet. Yeah, desalination consumes a lotta tera-watts. It'll be nice to save a few.
Maybe now they can get back to making a few more shovel-ready high-tech airplanes. Oh, wait, we have to crush a few cars first.
We have been polluting the water ever since the industrial age began and draining the water supply at the same time. Aquifers are getting depleted, its going to become an expensive problem. It is good to see this technology finally come about . It should help us bring water to arid lands. They say that with global warming it isn't the heat that is going to affect the plant life but the lack of water supply. It is an expensive proposition however to lay thousands of miles of pipe. But perhaps it will become cheap enough to take and desalinate water and fill up major rivers so that natural distribution can be restored. It would take a lot of energy to do it but with the two orders of magnitude cheaper maybe it would be cost effective? I would also suggest that we stop polluting the water with all the plastics and use it to recycle. We produce 37,000,000 tons of plastic each year that ends up in landfills and in the water. We could convert this into fuel energy. I have done a cost analysis on the energy from plastic recycling.
so after we've got these water chips, stimpacks, we setup the vaults and wait out the inveitable nuclear winter.
so who'll thinks they'll be a vault dweller? and would you be willing to venture out for a new chip?
If true, this technology effectively means the end of global warming and a magnificently richer world. Imagine how much carbon would be trapped on an emerald green Baja California peninsula. Green the the worlds ocean adjacent deserts and global warming becomes yesterdays news.
This is awesome! As the ocean levels rise from the melting ice caps, maybe we can drink our way to "save the beaches"!
Salt is a crystal formed by ionic bonds, there's no such thing as a salt molecule. They must be making holes small enough for a single sodium ion. Not sure why they need to tailor the holes for each chemical, though. Just make them a bit bigger than water molecules, right? Than I guess a second filter that's a bit smaller, to remove contaminants that are smaller...
Here in Australia most of the households use rain water, I'm not even connected to the town water (and I'n not a threehugger...).
The idea initially sounded weird (I'm from Europe), but it works fine and the quality is excellent, without fluoride and other craps.
Each hole also has a Maxwell's demon standing guard.
Reference (establishing that the claims of Lockheed-Martin's press release are thermodynamically bogus):
@article{Author = {Elimelech M. and Phillip W. A.},Journal = {Science Science},Number = {6043},Pages = {712--717},Title = {The future of seawater desalination: Energy, technology, and the environment},Volume = {333},Year = {2011}}
We still don't have a good solution for what to do with all the brine left behind, and ramping up production to this kind of degree will only make that problem much worse.
http://en.wikipedia.org/wiki/Viktor_Petrik
obviously, Lockheed Martin will be sued.
And that's almost all there's to it. The energy demands for desalination don't include, obviously, the material and energy costs of filter media and their maintenance. The subject technology is all about reducing those.
A successful API design takes a mixture of software design and pedagogy.
Now that's just dumb. You mix it with seawater to dilute it, and dump it back into the ocean. That's all there's to it.
A successful API design takes a mixture of software design and pedagogy.
Q: How do you turn a German beer into an American beer?
A: Filter it to get the raw sewage out, then refrigerate.
I've fallen off your lawn, and I can't get up.
So they're going to make water filters out of material whose fragments can be so small as to pass through the blood-brain barrier - what could possibly go wrong?
Once upon a time, asbestos was also considered a miraculous futuristic material with seemingly near limitless applications.