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'Green' Chemistry at Hampshire College

Monday, November 29, 2010

Pema Dorjee arrived at Hampshire College planning to study the social sciences. Danielle Nalband's intended focus was animal behavior. The influence of two professors working on "green" chemistry projects, however, drew both these recent graduates into the laboratory instead.

Dorjee came to Hampshire through an exchange program with his prior school, the Central Institute of Higher Tibetan Studies in Sarnath, India.

A Hampshire class on the environment and pollution sparked an interest in chemistry in combination with the social sciences. A summer internship with Professor Dula Amarasiriwardena cemented that interest.

"Working with Dula is so much fun," said Dorjee. "He knows so much and guides you through step by step. And, he's trying to use knowledge to do good things for communities."

In Dorjee's final year at Hampshire, the professor and student researched an innovative way to remove harmful metals from soil.

"He worked with me on nanoparticles, which is anything less than one billionth of a meter. At that dimension, chemical and magnetic properties change," saidProfessor Amarasiriwardena. "We synthesize these materials, and we are interested in their capabilities for environmental remediation, to absorb metals."

The specific nanoparticle Dorjee and Amarasiriwardena focused on is nanosized zero-valent iron, or nZVI for short. It's proven to be effective in soaking up antimony, a toxic metalloid similar to arsenic that's used in things like pesticides and to absorb heat in everything from bullets to brake pads. But there remain challenges that the student and professor worked together to overcome.

"You can put nZVI in a landfill, and if you have 100 grams of antimony, it becomes 50 in less than a minute," said Amarasiriwardena. "But if you put nZVI in the real world in soil, the soil has humic acids, which will reduce the effectiveness. Within eight minutes, it's ten times slower at bonding with antimony. It still absorbs, but the reaction is retarded."

Trying to find a way to keep the absorption rate high was something that appealed to Dorjee. At the Central Institute his studies were mostly in Buddhism, which helped to develop a socially conscious philosophy. In the nZVI research, he saw a way in which he could positively impact people's lives and the environment through "green" chemistry.

Rayane MoreiraCommunity awareness is something organic chemist Rayane Moreira is dedicated to as well. Her students also get involved in green chemistry, making large-scale synthetic processes more environmentally friendly.

She and Nalband have collaborated on research on the Diels-Alder reaction, a catalyzing reaction that produces six-membered carbon rings useful for many products like pharmaceuticals and plastics. Their goal is to contribute to finding a way to use water-based solvents instead of harsher chemicals currently used as catalysts in the reaction.

"The idea is to be able to make complex organic molecules without producing toxic waste. About 80 percent of the waste for industries like those that produce pharmaceuticals is organic solvents," said Professor Moreira. "They're nasty and toxic, some are carcinogenic, and most are flammable. It's a huge amount of problematic material. By far the best replacement would be water. If we could use that, we could change the way industry works."

Neither expects a quick, dramatic breakthrough, but Nalband hopes to make some progress towards a discovery.

"Developing an industrial sort of process takes a lot of time, funding, and manpower," she said. "It would definitely be a cleaner technology, an alternative to using these harmful, carcinogenic chemicals and starter materials."

Nalband served as a research leader for other chemistry students in her final year at Hampshire, and was a teaching assistant in Moreira's organic chemistry class. In a small lab group, she and others worked on getting synthetically useful materials from sugars. It was a positive experience, and Nalband has no doubts that her future career will center on laboratory research.

"I'm completely in love with this. This is what I want to do," she said, adding that she plans to work in industry at least a year before going on to graduate school.

Dorjee also plans to work as a laboratory technician before heading to graduate school. Like Nalband, he particularly hopes to use his chemistry background to make a positive impact.

"You can use your knowledge to bring good things to communities," he said.

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