Scientists Explore Invisible Environmental Helpers
This Behind the Scenes article was provided to LiveScience in partnership with the National Science Foundation.
For most, the word catalysis is not a household word. But this process, a way to speed up a chemical reaction using a “helper” material that survives largely unscathed, is a major driving force for everything from the petroleum and chemical industries to the understanding of environmental science or the inner workings of our cells.
“Chances are that most of the manufactured goods that you are in contact with right now contain some form of synthetic fiber – your clothes, the shoes on your feet, and the carpet just below them,” says Israel Wachs, a professor of chemical engineering at Lehigh University in Bethlehem, Pa. “It’s likely that all of them have been touched in some manner by catalysis.”
In fact, close to 20 percent of the United States’ GNP involves a product going through a catalytic processing step.
And yet, when Wachs ran the initial experiments that convinced him to study catalysis at the nanometer (billionths of a meter) scale, he was diving into uncharted waters.
“There were no rules established when we first got into this,” recalls Wachs, “no guidelines to follow. It was like not knowing which direction was up, down, left, or right. “
Wachs, is a recognized leader in the study of catalysis, a scholar whose work has been cited in the scientific literature more than 10,000 times throughout his career thus far. A serious and intense researcher, Wachs is not the kind of person to latch on to the latest fads.
During the 1990s, Wachs became aware, as many scientists did, of the growing buzz around the notion of nanotechnology. At the time he was skeptical, figuring that ‘nano’ might simply be the latest trend in the popular-scientific press, the type of thing that would inevitably blow over.
Despite his misgivings, he decided to run a few basic experiments to seek potential nano-applications in the realm of catalysis. The results of these experiments convinced him that ‘nano,’ in his field, was more than just hype.
These days, Wachs is advancing the science of nanocatalysis with help from a National Science Foundation NIRT (Nanoscale Interdisciplinary Research Team) grant that brings him together with collaborators from Lehigh, Rice University, and the University of Virginia -- research that has the potential to reduce pollution and impact the environment in a variety of ways.
“Nanotechnology deals with the manipulation of materials of incredibly small dimensions,” says Wachs. “At this scale, materials have unique chemical and physical properties not found in their larger counterparts, especially at one nanometer or less.”
To give a sense of the scale involved, imagine a strand of human hair. Now, imagine that same hair sliced lengthwise into 80,000 equal parts. The width of one of those slices would be about 1 nanometer.
Wachs maintains a unique research laboratory, the only one of its kind in the U.S., which uses a method called “operando molecular spectroscopy.” Operando is a Latin word that means operating. Operando spectroscopy allows for molecular-level monitoring of catalysts under realistic conditions that can be studied simultaneously online as it occurs. Through his research, Wachs has had many breakthroughs, even finding that the use of nanoparticles would actually be counterproductive for some catalytic reactions.
“Electrons behave differently at such a small scale,” he says. “So if a catalytic reaction requires a rich source of electrons, the use of nanoparticles is out. On the other hand, catalytic reactions that don’t require a rich source of electrons thrive at the nanoscale.”
For example, NOX is a pollutant created in automobiles, at many electric power plants and at other sources that contributes to a host of problems from the production of ozone (a greenhouse gas and ground-level pollutant) to acid rain. Wachs and his colleagues are currently trying to develop a nanocatalyst that converts nitrogen oxide (NOX) into the benign nitrogen and water.
This is not the first time, however, that Wachs has used his expertise in catalysis to positively impact major environmental issues. One of his three dozen patents is for a traditional catalytic process which converts methanol, a byproduct pollutant of paper mills, into formaldehyde that the mills can now use to make resins for particle board. The pulp mills once released this methanol along with other nasty chemicals into rivers and streams, resulting in environmental havoc. For the beleaguered paper industry, this, in essence, is the transformation of pollution into profits. In 2002, Wachs received the Clean Air Excellence Award from the EPA for his pioneering work in this area.
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Editor's Note: This research was supported by the National Science Foundation (NSF), the federal agency charged with funding basic research and education across all fields of science and engineering. See the Behind the Scenes Archive.
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