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Wed Mar 13, 2013, 07:17 AM

Pentagon weapons-maker finds method for cheap, clean water

WASHINGTON (Reuters) - A defense contractor better known for building jet fighters and lethal missiles says it has found a way to slash the amount of energy needed to remove salt from seawater, potentially making it vastly cheaper to produce clean water at a time when scarcity has become a global security issue.

The process, officials and engineers at Lockheed Martin Corp say, would enable filter manufacturers to produce thin carbon membranes with regular holes about a nanometer in size that are large enough to allow water to pass through but small enough to block the molecules of salt in seawater. A nanometer is a billionth of a meter.

Because the sheets of pure carbon known as graphene are so thin - just one atom in thickness - it takes much less energy to push the seawater through the filter with the force required to separate the salt from the water, they said.

The development could spare underdeveloped countries from having to build exotic, expensive pumping stations needed in plants that use a desalination process called reverse osmosis.

http://news.yahoo.com/pentagon-weapons-maker-finds-method-cheap-clean-water-051529904--finance.html

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Reply Pentagon weapons-maker finds method for cheap, clean water (Original post)
Sherman A1 Mar 2013 OP
hedda_foil Mar 2013 #1
Sherman A1 Mar 2013 #3
Orrex Mar 2013 #2
n2doc Mar 2013 #4
hunter Mar 2013 #5
EOTE Mar 2013 #7
hunter Mar 2013 #9
EOTE Mar 2013 #10
Victor_c3 Mar 2013 #6
Romulox Mar 2013 #8

Response to Sherman A1 (Original post)

Wed Mar 13, 2013, 08:57 AM

1. This actually sounds promising.

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Response to hedda_foil (Reply #1)

Wed Mar 13, 2013, 09:23 AM

3. It does indeed

Makes one just a tiny bit hopeful....

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Response to Sherman A1 (Original post)

Wed Mar 13, 2013, 09:04 AM

2. Quick! Weaponize it!

Hardy har har.

It seems to me that this would be useful for filtration even beyond salt-to-fresh water. I saw a TED talk about a similar technology used in Haiti and Louisiana following the disasters there.

Very promising!

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Response to Sherman A1 (Original post)

Wed Mar 13, 2013, 10:06 AM

4. Sounds good. I wonder if they are being over optimistic on time scales

2014 is just around the corner. Unless they have all the manufacturing kinks worked out it will take longer. Still, will be interesting to see if this works, and works cheaply enough for 3rd world use.

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Response to Sherman A1 (Original post)

Wed Mar 13, 2013, 12:16 PM

5. First fusion, now this bullshit.

Maybe something bad maybe is going to happen at Lockheed? Gotta pump up those share prices before the big sell.

It wouldn't surprise me if carbon nano-materials are the new asbestos, or some other sort of catastrophic liability is lurking in the wings.

In any case, current reverse osmosis materials are pretty good. Even with a thermodynamically ideal membrane, the energy cost of reverse osmosis is still high.

It's possible forward osmosis plants are more efficient when the energy source is a heat engine like a fossil fuel or nuclear plant because energy that might otherwise be dumped as heat can contribute to this process. The same might be true of solar desalinization.

Here's a DOE overview of membrane water processing technologies:

http://www.netl.doe.gov/technologies/pwmis/techdesc/membrane/index.html

Making water to safe to drink is a task comparable to delivering food. People don't starve because there's not enough food in the world, they starve because the distribution of food is impeded. Similar problems exist with safe drinking water supplies.

The problem of overall water supplies, for example water used for agriculture, industrial, and domestic use, is of a different nature. Beyond rainfall, delivering safe water requires a fully functional society, and delivering water to places where it must be pumped "uphill," either literally, or for long distances, or by some process of desalinization, requires a fully functional industrial society and a great deal of energy.

A simple improvement in membrane technology isn't any kind of game changer.

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Response to hunter (Reply #5)

Wed Mar 13, 2013, 01:54 PM

7. Why must this be bullshit?

And I seriously doubt that carbon-nano ANYTHING will be like asbestos. Carbon nanotubes are simply carbon, arranged very precisely into perfect little tubes. We've been exposed to carbon our whole lives, aside from hydrogen and oxygen (water), carbon is the most abundant element in our bodies. Why must a good discovery like this be looked upon with such scorn?

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Response to EOTE (Reply #7)

Wed Mar 13, 2013, 02:44 PM

9. It takes a certain amount of energy to desalinate water.

It's thermodynamics and math.

The best off-the-shelf membrane technology available today is close enough to the ideal membrane that an improved membrane technology isn't going to greatly reduce the cost of desalinated water. This may be a incremental improvement in the process, it may not be. But the overall improvement is limited by the physics.

As for cancer, the arrangement of these innocuous sounding materials is important. You might say asbestos is a mix of silicon, oxygen, and a couple of other non-toxic elements, or that benzene is a mix of carbon and hydrogen, yet both are carcinogens.

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Response to hunter (Reply #9)

Wed Mar 13, 2013, 03:35 PM

10. Yes, I'm very well aware that doing things requires energy.

The only issue is that current methods of desalinization ARE fairly inefficient, especially considering the cost of these devices and their availability. This sounds like it would be a far more efficient method.

And with regard to cancer, there are no materialS, this is simply carbon. We deal with carbon in countless different forms every day, even as a lone element. There is NO information that graphene, bucky balls, diamonds or carbon nanotubes are anything approaching carcinogens.

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Response to Sherman A1 (Original post)

Wed Mar 13, 2013, 01:47 PM

6. As a chemist, this is very interesting to me.

At a nanometer, you'd probably be able to removed most if not all other toxins as well. You'd definitely catch all of those larger organic contaminant molecules. I'm not an organic chemist, but I think 1 nanometer is roughly the length of a carbon-carbon bond (which is nothing)

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Response to Sherman A1 (Original post)

Wed Mar 13, 2013, 01:55 PM

8. How much energy is required to produce the carbon fiber membrane? nt

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