backtop


Print 74 comment(s) - last by 16nm.. on Jul 24 at 11:12 PM

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.



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

A Nice Cold Glass of Chlorine?
By DJWaffles on 7/23/2008 1:48:17 PM , Rating: 2
I don't know how much chlorine they use in this process but it would seem that de-chlorination would be kind of an important step in making water drinkable. I imagine it's not a health issue, but how good can it really taste?

Last time I checked swimming pool water isn't the most refreshing beverage.




By MegaHustler on 7/23/2008 1:58:48 PM , Rating: 2
If you're dying of thirst, it probably tastes a lot better than no water...

Seriously though, there are a lot of uses for desalinated water other than direct human consumption - watering crops for example.


By FITCamaro on 7/23/2008 2:07:19 PM , Rating: 2
You're not talking about enough chlorine to taste it. Fresh drinking water is already treated with chlorine.


RE: A Nice Cold Glass of Chlorine?
By nafhan on 7/23/2008 2:37:32 PM , Rating: 2
Actually chlorine levels in drinking water are comparible to chlorine levels in swimming pools. I remembered this from lifeguarding in high school, but I went ahead and looked it up anyway: "a pool is treated at a rate of 3 PPM, and drinking water is treated at anywhere from 0.2 PPM to 3 PPM".
from http://science.howstuffworks.com/question189.htm

There is a lot of other crap (sometimes literally) in swimming pool water that probably helps give the water that "distinctive" swimming pool taste.


RE: A Nice Cold Glass of Chlorine?
By Smartless on 7/23/2008 2:52:52 PM , Rating: 2
True about the chlorine treatment but you also have to consider that drinking water is normally treated once depending on the contact time and the source. Swimming pool water is kept at a constant. Hehe and if the water has trace amounts of salt in it, much worse taste.


By masher2 (blog) on 7/23/2008 10:08:03 PM , Rating: 2
Swimming pool water (mine at least) also contains algicides, some type of flocculant, and a little muriatic acid to stabilize the p.h.


"Let's face it, we're not changing the world. We're building a product that helps people buy more crap - and watch porn." -- Seagate CEO Bill Watkins

Related Articles













botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki