18 January 2008
Young Innovator Profile: Michael Wong
Describing his idea to use gold to clean up toxic waste, Michael Wong says, “I admit it does sound crazy.” Wong plans to combine gold with palladium — an even more precious metal — to treat polluted groundwater beneath waste dumps and contaminated factories and military sites. “It not only works faster [than current methods], but a hundred times faster,” Wong says, “and I bet it will be cheaper too.”
A golden detergent? Here is Wong’s trick: He creates nanoparticles of gold. In his realm, the work product is measured not in carats but in atoms. A thimbleful of coffee-colored solution contains 100 trillion gold spheres — each only 15 atoms wide, or about the width of a virus. Upon every golden nanosphere, Wong and his team dust a dash of palladium atoms. Think of an infinitely small ice cream scoop flecked with sprinkles.
The 35-year-old graduate of the California Institute of Technology and the Massachusetts Institute of Technology says Wong had not given toxic waste much thought until three years ago, when one of his colleagues at Rice University (where he is a recently tenured professor of chemical engineering) came to him and said, “I have a problem,” meaning something interesting to work on.
The problem concerned the suspected carcinogen trichloroethene, or TCE, “one of the most ubiquitous pollutants out there,” says Wong, and “a really nasty molecule.” The clear, sweet-smelling solvent has been used for decades to degrease metal parts in factories and government facilities.
TCE lingers like a bad houseguest, especially if handled carelessly. It accumulates in soil and can persist for years in groundwater. In a report last year, the National Research Council found that TCE was a potential cause of kidney cancer; it’s also associated with liver problems, autoimmune disease, and impaired neurological function.
Currently, the most common method of removing TCE from groundwater is to “pump and treat,” Wong says — to pump the water out of the ground and run it through a filter made of activated carbon. The carbon grains soak up TCE like a sponge, but the process leaves behind TCE-laden filters that have to be stored or burned. “So you haven’t really gotten rid of anything,” Wong says. “You’ve just moved it from one place to another.”
This is where Wong comes in. He began thinking about using nanoparticles as a catalyst to react with the TCE and break it down into what he calls “happy by-products.”
From the scientific literature, Wong knew that palladium had shown some promise at deconstructing TCE. So he and his team began trying various recipes, and after six months reached a eureka moment when they sculpted a palladium-covered core of gold atoms.
“We didn’t believe it at first, because the gold-palladium nanoparticles were just so much more efficient — like, a hundred times more efficient,” he says. “You see, gold itself doesn’t do anything to TCE.” But something very interesting happens at the interface where gold, palladium, and TCE meet.
Wong’s nanodetergent breaks down TCE into relatively harmless ethane and chloride salts. He and his team are now working with engineers to build a real-sized reactor to field-test the nanoparticles at a polluted site. They hope to be scrubbing TCE in about a year, and then they’ll see whether they have the cost-efficient cleaner they seek.
Wong was born in Quebec City, Quebec, and grew up in Sacramento, California. His father owned a strip mall where a tenant's dry-cleaning business became contaminated with a chemical cousin of TCE. Wong said his father was held legally responsible and fined tens of thousands of dollars. “So my dad has a real interest in my work,” said Wong. “He keeps telling me, ‘Hurry up, son!'"
This article is excerpted from “Midas Touch” by William Booth, which originally appeared in SMITHSONIAN, October 2007. Booth is a reporter for The Washington Post who is based in Los Angeles.
The opinions expressed in this article do not necessarily reflect the views or policies of the U.S. government.
