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A plasma reactor that could be attached to the exhaust system of motor vehicles to dramatically reduce harmful emissions has been developed by researchers at Old Dominion University's Frank Reidy Research Center for Bioelectrics.

Karl Schoenbach, Batten Endowed Chair for Bioelectrics at ODU and director of the Reidy Center, together with Muhammad Arif Malik, a Pakistani scientist who was a visiting researcher at the center in 2003, received a U.S. patent for the reactor in November.

The patent was assigned to the ODU Research Foundation.

Schoenbach described Malik, who now works in Pakistan, as a "very skilled scientist and the winner of a major award in chemistry in his country" who had done research previously using cold plasmas in decontamination projects. Malik came to Norfolk under a grant that allowed him to work with Schoenbach, who is a pioneer in plasma research, and to study the effect of cold plasmas on chemicals in air and water.

The collaboration "discovered something that was surprising to us," Schoenbach said. "By squeezing the discharge plasma between insulating plates the efficiency of decontamination was increased dramatically."

An example of a reactor that could be placed within the exhaust system of a motor vehicle helps to explain the invention. The use of plasmas to treat engine exhaust was proposed years ago. (Electrons in supercharged plasmas bombard emission gases such as nitrogen oxides, turning noxious molecules into molecules of more benign gases.) But a conventional device to produce low-temperature plasmas requires too much energy to be a feasible anti-pollution device, Schoenbach said.

Malik's and Schoenbach's idea was to change the design of the reactor, which conventionally has two plates perhaps one centimeter apart that create a plasma discharge between them. Instead, the new reactor has several plates and they are much closer together. "It's a simple change in geometry that takes the idea beyond state-of-the-art," Schoenbach said.

Researchers at ODU believe such a reactor could efficiently split the molecules of harmful emissions at a cost that could be attractive to motor vehicle manufacturers. The application potentially could be used by many other industries whose processes and products create harmful chemical emissions, Schoenbach said.

According to the U.S. Patent and Trademark Office: "A novel plasma reactor is provided that includes a discharge chamber with dimensional characteristics and configuration of dielectric and electrodes that optimize efficiency based on the characteristics of the corona discharge streamers generated…. The present invention is able to achieve improved energy efficiency while preserving effectiveness for gas treatment."

Schoenbach said more research needs to be done on the "squeezed" reactor and that he and the ODU Office of Research will be making contact with potential investors.
"We need to present this technology at trade shows and talk with entrepreneurs," he said. "The groups that might develop a concept such as this are not the same crowd that goes to scientific conferences or who read scientific journals."

This article was posted on: December 6, 2007

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