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nanotimes News in Brief

11-01 :: December 2010 / January 2011

Viruses // Rice Discovery Greatly Improves Common Disinfectant

akthrough from the Rice University labs of Andrew Barron and Qilin Li. The Rice professors and their team reported in Environmental Science and Tech- nology that adding silicone to titanium dioxide, a common disinfectant, dramatically increases its ability to degrade aerosol- and water-borne vi- ruses.

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“We‘re taking a nanoparticle that everyone‘s been using for years and, with a very simple treatment, we‘ve improved its performance by more than three times without any real cost,” said Barron, Rice‘s Charles W. Duncan Jr.-Welch Professor of Chemistry and a professor of materials science. Barron descri- bed himself as a “serial entrepreneur,” but saw the discovery‘s potential benefits to society as being far more important than any thoughts of commerciali- zation. Barron said titanium dioxide is used to kill viruses and bacteria and to decompose organics via photocatalysis (exposure to light, usually ultravio- let). The naturally occurring material is also used as a pigment in paints, in sunscreen and even as food coloring.

“If you‘re using titanium dioxide, just take it, treat it for a few minutes with silicone grease or silica or silicic acid, and you will increase its efficiency as a catalyst,” he said. Barron‘s lab uses “a pinch” of sili- con dioxide to treat a commercial form of titanium

simple technique to make a common virus-kil- ling material significantly more effective is a bre-

dioxide called P25. “Basically, we‘re taking white paint pigment and functionalizing it with sand,” he said.

Disinfecting a volume of water that once took an hour would now take minutes because of the material‘s enhanced catalytic punch, Barron said.

“We chose the Yangtze River as our baseline for testing, because it‘s considered the most polluted river in the world, with the highest viral content,” he said. “Even at that level of viral contamination, we‘re getting complete destruction of the viruses in water that matches the level of pollution in the Yangtze.”

Using a smaller amount of treated P25 takes longer but works just as well, he said. “Either way, it‘s green and it‘s cheap.”

The team started modifying titanium dioxide two years ago. Li, an assistant professor in civil and en- vironmental engineering whose specialties include water and wastewater treatment, approached Barron to help search for new photocatalytic nanomaterials to disinfect drinking water.

The revelation came when students in Barron‘s lab heated titanium dioxide, but it wasn‘t quite the clas- sic “aha!” moment. Graduate student and co-author Michael Liga saw the data showing greatly enhan- ced performance and asked fellow graduate student