Eating Arsenic and Old TCE

What’s new and small and eats arsenic and old TCE (trichloroethylene) spills? It’s nanotechnology, and it might be coming soon to a hazardous waste site near you.

Nanotechnology might offer some of the quickest, cleanest ways on the horizon to treat contaminated water. Consider, for example, a new nanomolecule that speeds up the breakdown of TCE in groundwater by “many orders of magnitude,” according to its co-creator Michael S. Wong, assistant professor of chemistry and biomolecular engineering at Rice University.

“It breaks down into ethane and chloride salt, which are both fairly harmless,” he says. “Nature itself actually can get rid of a lot of chemicals, but very slowly. Our catalyst kick-starts the reaction and accelerates it.”

Initial trials were so surprisingly successful, he says, that work is underway to do controlled trials at actual sites. Wong and his colleagues plan to construct a larger tank with the catalysts inside, run contaminated water into it, and see how well the nanocatalyst works in breaking down TCE from real spill sites.

Wong’s is not the only research that could someday be used to clean up the mess left by previous generations of chemicals. Nanotech can also bind arsenic to iron, so magnets can draw out the iron-bound arsenic. And since arsenic in drinking water is a problem around the world, including many places in California, such technology could offer hope for communities worldwide where finding uncontaminated drinking water occupies much of residents’ time and energy.

All of which goes to show that to abandon all nanotechnology because of concerns about its safety might do more harm than good. As research by Cornell law professor Kysar and others has shown, people often overestimate the risks of new technology and underestimate its benefit. “We tend to think that anything that has a high risk has a low benefit, and that’s just not true,” Kysar says.

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