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Green chemistry is cleaning up pollution—and preventing it in the first place.

by Kim Ridley with Terry Collins

Industrial chemistry is a dirty business. More than 100,000 synthetic chemicals have been released into our air, water, soil and food, and few have been tested for health effects on human beings or other creatures. The consequences can be debilitating and even deadly as science continues to link exposure to industrial chemicals with diseases and disorders including cancer, reproductive problems, learning and immune system disorders and birth defects.

Terry Collins, director of Carnegie Mellon University’s Institute for Green Oxidation Chemistry, is creating chemicals that don’t pollute in the first place. He’s among the leaders of green chemistry, an emerging technology that makes new molecules that are safe by design. Green chemists avoid toxicity in new chemical products and processes by following “nature’s recipe book,” which uses elements that are commonly found in the living world.

Collins and his colleagues have invented nontoxic chemical catalysts that dramatically boost the power of one of nature’s miracle cleaners: hydrogen peroxide. Our bodies make hydrogen peroxide every day to destroy toxicants. Mimicking this process, Collins and his colleagues have created molecules called TAML activators, which work with hydrogen peroxide to clean up industrial pollution—and prevent it from happening in the first place.

While proving that it’s possible to create safe chemicals, Collins also talks his walk. He has effectively and courageously challenged industry spin-doctors for years about the perils of chlorinated byproducts. He talks with Kim Ridley about chemistry’s next revolution.

What inspired you to become a green chemist?

When I was a post-doc at Stanford University, I’d sit in the library on Saturday morning daydreaming about what the heck I was going to do in my own career. I’d always had an interest in toxicity and I was working with a group studying how various enzymes activate oxygen and hydrogen peroxide and trying to produce technologies mimicking this. At that time, chlorinated byproducts in drinking water, particularly chloroform, were being linked with cancer. I thought, wouldn’t it be incredible if we could disinfect water using a reagent that nature employs to break down chemicals, hydrogen peroxide or oxygen, rather than our manufactured chlorine. I came up with a design protocol that evolved from my initial thoughts in the Stanford Chemistry library, and fifteen years later, we had a catalyst.

How does green chemistry differ in approach from conventional chemistry?

In my worldview, green chemistry should always ask: is it good for babies? Or more significantly, is it bad for babies? If it’s bad for babies don’t do it. That’s what we’ve got to get ingrained into our field. That, of course, opens a whole new set of questions like, how do you understand whether some chemistry is or is not bad for babies? That then brings up the remarkable fact that chemists are not trained in toxicity and ecotoxicity. With conventional chemistry, we’re giving people the keys to cars without any driver training.

This is yet another one of the major changes that needs to occur in the collective academy. The toxicologists and chemists need to start talking a lot more, and the educational edifice of chemistry has to begin as quickly as possible to incorporate a fundamental understanding of toxicity. We should all be doing this because ultimately, the central issue is this: It is an inescapable responsibility of chemists that they should build the technological dimensions of a sustainable civilization.

Is it really possible to avoid unforeseen consequences when inventing new substances?

Whenever anybody is designing a new technology, there is always the potential that there will be a problem in the future. For example, people who initially developed phthalates, bisphenol-A, and other major chemicals had absolutely no idea that they would disrupt the endocrine function of all sorts of creatures. At first, they looked like the most extraordinarily innocent and nice little molecules, and phthalates even smell nice. But what’s unfolding now is an understanding of the ability of various synthetic compounds to interfere with hormonally controlled development.

Anybody developing a technology has to live with that uncertainty, but one thing we can do is to avoid the known mistakes. We pay a lot of attention to this in the design of TAML activators. When you look at where most of the ecotoxicity is coming from, the answers are relatively simple. Many of our big toxicity problems are simply elemental in origin. They occur because we are putting into a distributive technology an element that is not commonly encountered in the biosphere. Lead and mercury are classic examples. When you’re designing green chemistry that’s relatively easy to avoid. You can make the intellectual decision to only to use elements that are commonly employed in biochemistry.

At the same time, green chemists need to study the toxicity of the technologies they’re creating, and if something bad comes up that they didn’t expect, they need to be prepared to abandon the technology. One of the very profound lessons from the last century is that persistent, bioaccumulative compounds, particularly those that are mobile in the ecosphere, are going to wander around looking for trouble to cause and they’re often going to find it. So another thing not to do is to make these substances and put them into distributive technologies. Ultimately, if we can move the elemental composition of our technologies closer to the elemental composition of life and avoid using persistent, environmentally mobile compounds, we can stay away from a lot of trouble.

What are some of the most promising applications of TAML activators?

Sometimes the only way to get rid of a pollutant in water is to burn it. The TAML activator plus hydrogen peroxide breaks down pollution by the same sort of chemistry. It’s mechanistically different from burning, but with the same result. And so you can get rid of a large number of pollutants in water without combustion and this has real potential to be a lot cheaper and simpler to do.

There are several promising applications to clean up and reduce pollution from paper mills. For example, effluent streams from some paper mills around the world are turning rivers dark colors and paper mill pollution has a foul smell. We can really help there. A tiny quantity of our TAML catalyst and a small amount of hydrogen peroxide can rapidly get rid of most of the color. TAML technology can also easily ameliorate the smells associated with pulp mills. And you can use the catalyst and hydrogen peroxide instead of chlorine to bleach wood pulp for high quality paper.

This technology can also break down invisible pollutants like organochlorines. For example, we have shown that chlorinated phenols, including the legacy wood preservative pentachlorophenol (PCP), an EPA priority pollutant and a very tough molecule to destroy, can be completely degraded to harmless products in minutes at room temperature and pressure without measurable production of dioxins. This dioxin point is important because fungi actually degrade PCP by related chemistry, but produce trace dioxins in the process.

In addition, this technology also can disinfect water. We have demonstrated this clearly with spores, which are the most difficult pathogens to kill, and we are now turning our attention to the other types of pathogens including protozoa, fungi, viruses, and vegetative bacteria. TAML technology has a phenomenal ability to kill spores and so it could become a mainline defense against anthrax attacks in the future. You also can use it to break down chemical warfare agents such as sulfur mustard. We have tested four common thiophosphate pesticides and these are all easily destroyed, as are their often-toxic residuals that are produced from existing breakdown procedures. And we can easily decompose many other pathogens and pollutants. We will be writing about these and other novel applications in the coming years.

Is this technology being widely used?

It’s a question now of production, volume and cost. There’s a lot of activity right now about next steps and strategies for large-scale commercialization. The catalyst is licensed for several applications, and I receive requests every week from companies interested in exploring TAML uses.

Many companies have issues with effluents that are very expensive to handle. For example EDTA, a chelating agent that has many uses, often becomes a big time pollutant at the end of its use in the economy. Our prototype catalyst that’s heading into commercialization decomposes it with peroxide quite effectively.

It’s hard to say when we’ll see big scale uses, but obviously the sooner the better. That’s where the focus is right now and there’s a distinct possibility that Pittsburgh, which is an icon of a city putting itself back together in first class style from a highly polluted past, might become a major center for green technology. This idea is very attractive to people in the region, and the ideal situation would be to employ people here to make and market the catalyst.

What are the chances of shifting the chemical industry in a more sustainable direction?

Sustainability doesn’t just mean feeling positive about the direction of our civilization. It’s also about fundamental strategic stability in the stock market, which is why change is going to happen.

Look, for example, at the lead industry and the damage it has done and the consequences that are now accruing. Americans lost IQ across the whole population because of lead in gasoline and paint. A court in Rhode Island recently said that the lead-based paint industry—Sherwin-Williams; NL Industries, Inc.; and Lyondell Chemical Co., the parent company of defendant Millennium Holdings LLC—are to blame for the lead poisoning of Rhode Island children and Rhode Island is holding them fiscally responsible.
What this means for the future of the evolution of the economy is that polluters can be held accountable decades after the people who originally made the decisions are long gone. So people will realize that it’s much smarter to invest in the stock market in companies that are producing safe products rather than in companies that are not dealing with their pollution and especially pollution that harms children.

I’m very optimistic. The three big technology areas for sustainability are safe energy, which has nothing to do with fossilized carbon or nuclear power, but will be solar based; renewable feed stocks; and a nonpolluting technology base. These things are not only doable; they’re inspiring to contemplate, wonderful to watch in progress, and fun to work on.

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