[chilefuturo] Interesante tecnologia para purificar agua.
- From: Jaime Aravena <jaravena@xxxxxxxxx>
- To: chile futuro <chilefuturo@xxxxxxxxxxxxx>
- Date: Fri, 3 Sep 2010 07:58:18 -0700 (PDT)
Parece que cada dia estamos mas atras. El apagon cultural se ensancha.
Creo que estamos en vias de subdesarrollo y dependencia.
Esta tecnologia parece muy prometedora. ¿Se investiga sobre estro en CHile?
¿sabe alguien?
http://www.elektor.com/news/electrified-nano-coated-cotton-purifies-water-at.1514639.lynkx?utm_source=UK&utm_medium=email&utm_campaign=news
Electrified nano-coated cotton purifies water at low cost
Publication date: 2 September 2010
Stanford researchers have developed a water-purifying filter that makes the
process more than 80,000 times faster than existing filters. The key is coating
the filter fabric – ordinary cotton – with nanotubes and silver nanowires, then
electrifying it. The filter uses very little power, has no moving parts and
could be used throughout the developing world.
By dipping plain cotton cloth in a high-tech broth full of silver nanowires and
carbon nanotubes, Stanford researchers have developed a new high-speed,
low-cost filter that could easily be implemented to purify water in the
developing world.
Instead of physically trapping bacteria as most existing filters do, the new
filter lets them flow on through with the water. But by the time the pathogens
have passed through, they have also passed on, because the device kills them
with an electrical field that runs through the highly conductive "nano-coated"
cotton.
In lab tests, over 98 percent of Escherichia coli bacteria that were exposed to
20 volts of electricity in the filter for several seconds were killed. Multiple
layers of fabric were used to make the filter 2.5 inches thick.
"This really provides a new water treatment method to kill pathogens," said Yi
Cui, an associate professor of materials science and engineering. "It can
easily be used in remote areas where people don't have access to chemical
treatments such as chlorine."
Cholera, typhoid and hepatitis are among the waterborne diseases that are a
continuing problem in the developing world. Cui said the new filter could be
used in water purification systems from cities to small villages.
Filters that physically trap bacteria must have pore spaces small enough to
keep the pathogens from slipping through, but that restricts the filters' flow
rate.
Since the new filter doesn't trap bacteria, it can have much larger pores,
allowing water to speed through at a more rapid rate.
"Our filter is about 80,000 times faster than filters that trap bacteria," Cui
said. He is the senior author of a paper describing the research that will be
published in an upcoming issue of Nano Letters.
The electrical current that helps do the killing is only a few milliamperes
strong – barely enough to cause a tingling sensation in a person and easily
supplied by a small solar panel or a couple 12-volt car batteries. The
electrical current can also be generated from a stationary bicycle or by a
hand-cranked device.
The low electricity requirement of the new filter is another advantage over
those that physically filter bacteria, which use electric pumps to force water
through their tiny pores.
SourceStanford News
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