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New membrane will help to ensure many parts of the world have easy access to drinking water.

One of the biggest, but least appreciated problems facing many regions of the world is lack of clean drinking water, a common problem in impoverished nations.  Ironically, many of these nations rest beside large bodies of salt water. Ttypically, processing salt water into fresh water is expensive and requires large dedicated plants.

DailyTech previously chronicled how wind-power driven desalinization plants which used membranes were being developed.  Now another major breakthrough in the field has been devised, this time concerning the membranes.

Researchers from several international universities have developed a chlorine-tolerant membrane which turns salt water into clean drinking water.  Typically, salt water is treated with chlorine to remove bacteria and microorganisms that would grow and form a biofilm on the membrane, blocking it.  However, chlorine destroys past membranes which were build using amide-polymers (nitrogen based).  This meant that that the water had to be dechlorinated before being sent to the membrane, a relatively expensive and complex process.

The new membrane is formed from sulfonated copolymers.  It took researchers Professor Benny Freeman with the The University of Texas at Austin, James E. McGrath of Virginia Tech University, and Ho Bum Park of the University of Ulsan in South Korea three years to develop the membrane for which they have filed a patent.  The new membrane is resistant to chlorine allowing the elimination of dechlorination.

Says Professor Freeman, "If we make the desalination process more efficient with better membranes, it will be less expensive to desalinate a gallon of water, which will expand the availability of clean water around the world.  It promises to eliminate de-chlorination steps that are required currently to protect membranes from attack by chlorine in water.  We believe that even a small increase in efficiency should result in large cost savings."

Researchers also believe the design will help reduce carbon dioxide emissions in developing nations by decreasing the electrical needs of the generation process. 

Professor Freeman explains:

Energy and water are inherently connected.  You need water to generate power (cooling water for electric power generation stations) and generation of pure water requires energy to separate the salt from the water. That energy is often generated from the burning of fossil fuels, which leads inevitably to the generation of carbon dioxide. Therefore, if one can make desalination more energy-efficient by developing better membranes, such as those that we are working on, one could reduce the carbon footprint required to produce pure water.

It was a combination of luck and hard work that brought the researchers upon the novel suflonated class of membranes.  This class of materials enjoys a high tolerance to aqueous chlorine, making it surprisingly a far better fit than membrane materials currently in use.

Professor Freeman, who holds the Kenneth A. Kobe Professorship in Chemical Engineering and the Paul D. & Betty Robertson Meek & American Petrofina Foundation Centennial Professorship in Chemical Engineering, states, "Basically, Dr. McGrath radically changed the chemical composition of the membranes, relative to what is used commercially, and the new membranes do not have chemical linkages in them that are sensitive to attack by chlorine."

The research was funded by the Office of Naval Research and the National Science Foundation-Partnerships for Innovation Program. 

The findings will be reported in a paper in this month's edition of the German Chemical Society's journal, Angewandte Chemie, with Mehmet Sankir and Zhong-Bio Zhang, both of Virginia Tech, as additional coauthors.



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RE: Swank.
By masher2 (blog) on 7/23/2008 7:01:42 PM , Rating: 5
> "Georgia may need it as well. They've got your man made lake, Lake Lanier, and they didn't spare them a near-crisis last year. "

The "near crisis" is because the Army Corp of Engineers is required to release 3.2 billion gallons a day from Lake Lanier -- every day, crisis or not -- to help protect endangered species downstream.

They also accidently released some 23 billion gallons extra over a two month period, due to faulty gauge, but the Atlanta water crisis was purely a manmade incident.

As for Florida's Everglades, before man began tinkering with the ecosystem there, South Florida was a malarial swamp, wholly unfit for human habitation. Most people consider malaria a tropical disease, but in the 1800s, it was a widespread, wholly "American" disease...eventually stamped out due to our efforts to control the environment.


RE: Swank.
By Ringold on 7/23/2008 9:37:57 PM , Rating: 2
I was aware of what was wrong with Lanier, but if they're going to keep pumping the water to keep the environmentalists happy (there's also some minimum flow needed for some power plants here in FL if I recall) then that will ultimately have to come from somewhere. The long-lasting drought doesn't help, either. They, like we here in Florida, face a potential looming water shortage regardless of cause, I was just defending desalination, which could (at a cost) make water shortages history.

That all may be true of the Everglades, and I'm not GreenPeace type, but if we consider it to be a special habitat worthy of conservation it would've been cheaper, perhaps, to not have wrecked it initially and planned growth a bit better rather than now be paying billions out the nose to pseudo-restore it. Billions of taxpayer dollars, no less.

I also know some conservative folk that have lived and gone fishing and hunting around in Central Florida long enough to see the damage done to the lake system around here, such as lakes that one could previously see to the bottom now resembling pea soup. Lake Apopka was a giant septic tank until only the last few years -- and it smelled like it any time I flew overhead, several thousand feet up. Could also often see a sort of oily film across its entire surface, but that was many years back now. I can point my finger at needless environmental damage without being a flaming liberal. ;)


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