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How scientists made a cheap new filter to purify water

By | August 31, 2010, 5:53 PM PDT

Standford University researchers developed a cheap water filter that could help purify water in the developing world — providing a new way to treat waterborne diseases like cholera, typhoid, and hepatitis.

The filter is cheap and kills off most bacteria it touches.

After purchasing the cotton fabric at Wal-Mart, the scientists wove it into a filter by immersing it in a solution of carbon nanotubes. After the scientists let the fabric dry, they dipped it into silver nanowire solution.

And voila, the scientists created a filter that can work 80,000 times faster than traditional filters.

In laboratory tests, the new type of filter killed 98% of the Escherichia coli bacteria. All it took was a few layers of the fabric filter and a charge of 20 volts of electricity.

The filter is fundamentally different than the filters on the market because it doesn’t attack the bacteria physically. It actually lets the bacteria pass through, killing it as it slips through its electrical field.

“This really provides a new water treatment method to kill pathogens,” Stanford engineering professor Yi Cui said in a statement. “It can easily be used in remote areas where people don’t have access to chemical treatments such as chlorine.”

How did Cui know it would work? He knew silver had a reputation as a bacteria killer.

Cui said before people had refrigeration and pasteurization, people would go as far as putting silver dollars in their milk and sometimes even put the money in their mouth. Gulp.

Thanks to gravity, the water pours right on through — so no pump is necessary!

The energy requirement is so low, Cui figures the filter could be powered by batteries, by riding a stationary bike, or by simply turning your hand.

Bye, bye bacteria?

Photo: Yi Cui, Stanford University

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Boonsri Dickinson

About Boonsri Dickinson

Boonsri Dickinson was a contributing editor for SmartPlanet from 2010 to 2012.

Boonsri Dickinson

Boonsri Dickinson

Contributing Editor

Boonsri Dickinson is a freelance journalist based in San Francisco. She has written for Discover, The Huffington Post, Forbes, Nature Biotech, Technewsdaily.com, Techstartups.com and AOL. She's currently a reporter for Business Insider. She holds degrees from the University of Florida and the University of Colorado at Boulder.

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Boonsri Dickinson

Boonsri Dickinson

In the unlikely event that Boonsri has a professional or financial relationship with a company she writes about, it will be prominently disclosed.

She writes for SmartPlanet and is not an employee of CBS.

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RE: How scientists made a cheap new filter to purify water
This is great news. Perhaps it can be expanded to take the other hazardous wastes out of water. The heavy metals and harmful chemicals.

The we could all get safe, clean water. I'm sure the market would buy this in droves. And if it can eliminate hazardous wastes, then it would be easy to get water polluting factories to use it as well.

No one wants polluted water.
Posted by Albee_Freeoneday
1st Sep 2010
+1 Vote
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RE: How scientists made a cheap new filter to purify water
We have been using silver (along with copper and lately zinc) to purify hot tub water for decades. It's the only accepted method of eliminating chlorine in your hot tub...

http://www.almostheaven.net/aho/ionizers.htm

NASA used silver to purify water in the Apollo moon program, and it's still used in the eyes of newborns and on burn patients. If big pharma had their way, though, no one would know about silver!
Posted by omb00900@...
1st Sep 2010
+1 Vote
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RE: How scientists made a cheap new filter to purify water
Big pharma makes plenty on collodial silver, trust me.

As to this filter, this is revolutionary. I just hope it is true and not a room temperture fusion project failure.
Posted by IMWeira
1st Sep 2010
+1 Vote
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RE: How scientists made a cheap new filter to purify water
What about the chemical pollution in water?
Posted by jujupang
23rd Feb 2011
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