ASU Research E-Magazine: Scrubbing Air

International Technology (IT) Corporation, a leading environmental management company based in Torrance, Calif., has licensed Arizona State University’s patent for a chemical process that cleans up toxic industrial solvents in air.

The process is called “photocatalytic oxidation (PCO) of environmental pollutants.” PCO is a method for removing organic pollutants such as trichloroethylene (TCE), trichloroethane (TCA), and benzene out of air as well as ground water.

Gregory Raupp, an associate professor of chemical engineering, began developing the invention in 1987 with Lynette Phillips, an ASU doctoral student who graduated in 1989. The project has brought more than half a million dollars in research support to Raupp’s lab in the past year.

The 1990 Clean Air Act Amendment has helped to create a multimillion-dollar market for the invention. The process could be used to help eliminate solvent emissions in dry-cleaning operations. Universities and high-technology industries could use it to reduce the chemical emissions vented from their laboratories and fabrication facilities.

Ideally, environmental clean-up methods would be fast, consume little energy, and produce no harmful by-products. “We have a process that appears to satisfy all the criteria,” Raupp says.

The ASU process requires a gas-flow device, ultraviolet light, and titania, a substance that spurs chemical reactions. As the gas flows over the titania under ultraviolet light, the organic pollutant is absorbed onto the catalyst, then chemically changes mostly into carbon dioxide and water vapor.