`Green' chemistry research project receives national award

Craig Hill, professor of chemistry, and visiting scientist Ira A. Weinstock, a chemist at the U.S. Department of Agriculture (USDA) Forest Service Forest Products Laboratory (FPL), received a national research award this summer that recognized the excellence of their research group's results and the group effort itself. The USDA Group Honor Award for Excellence they received was for their work to create a process that has immediate industrial applications to convert trees to paper without pollution.

"This award recognizes our group research efforts which led to the issuing of patents that put us in a position to work with industry; we have a strong, viable, promising product," said Hill. Only one of these awards is given each year for research excellence within the USDA.

Nearly a dozen researchers are involved with the project, which has received some $10 million in funding from the USDA, the U.S. Department of Energy (DOE) and other sources over the past five years. Research team members, located at Emory, the Forest Products Lab and the University of Wisconsin, are developing a new approach to the bleaching and conversion of wood pulp to paper. "Basically, we're creating a process that mimics biology," said Hill.

This new approach involves the use of inorganic mineral cluster compounds called polyoxometalates (POMs). The first step of the technology involves the direct oxidative degradation of wood pulp by the POMs to separate the two major components of wood--lignin, which imparts the color, texture and other properties to trees, and cellulose, which imparts the strength to trees and paper and is the basis for most paper materials. The partially oxidized and degraded lignin fragments and POMs are then filtered off, leaving white cellulose that is ready to be made into paper. The lignin fragments and POMs are then treated with air at high temperatures and pressures to turn the POM back into its original form and convert all the waste products from the bleaching step into carbon dioxide and water. The technology is environmentally friendly in that it uses oxygen, not chlorine, as the oxidant, uses only water as a solvent, produces no toxic organic compounds and generates only carbon dioxide and water.

Weinstock, who is spending this year at Emory as a visiting scientist, was a student at MIT when he first connected with Hill. "Craig gave a talk when I was a grad student, and I knew of his work on creating enzyme analogs that could be used in industry," said Weinstock. "In 1991 I wrote to him to see if he would be interested in working on this project, and he was."

Hill and Weinstock have received three patents on their work so far. "Now the work is moving out of the lab and into industry," said Hill. "There are members of an international consortium of pulp and paper companies that are going to fund pilot-scale trials," said Hill. "Our recent patents deal with the engineering process design of making our science work for industry. This program has promise and has the full support of industry and government."

"In 1991, the Forest Service took a risk on funding our project and committed several of our FPL scientists to work on it," said Weinstock. "This project is in line with the U.S. Forest Service's commitment since its inception early in this centry to use national forests as a managed resource, in addition to recreation. Additionally, the Department of Energy has given major support for our work because they see it as a way to reduce the paper industry's reliance on electricity in the paper making process."

Hill's and Weinstock's research is part of the "green" chemistry movement, which emphasizes developing chemical processes in ways that are more sustainable. "We have an industrial process that mimics a natural process," said Hill. "Ours is a post-industrial vision, a sustainable way to come at these products. Using nature as a paradigm of what's possible, there are things we can do that nature can't do, because we have access to catalysts and systems that aren't abundant in nature. We're combining molecular science with something that's actually useful."

--Jan Gleason

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