(166b) Free Radical Chemistry as the Underpinning for Advanced Oxidation Processes

A group of free radical based destruction technologies has emerged that are commonly referred to as advanced oxidation processes (AOPs). For example, processes that are being studied include ozone, ozone in combination with UV light or hydrogen peroxide. There are also process's that result in both oxidizing and reducing species that are under investigation, including heterogeneous catalysis, with TiO2 the most widely catalysis, sonolysis, and the electron beam process. The increased emphasis results from the recent shift in treatment philosophy to change from phase transfer, aeration stripping or activated carbon, to destruction technologies. A fundamental understanding of the chemistry of new environmental technologies is critical to the appropriate application of the processes to solve complex environmental problems. With the increased concern in sustainability of drinking water supplies we feel that the application of these processes will increase. As the importance of water reuse increases the application of advanced technologies will also likely increase. We have initiated a long-term program in developing a better understanding of free radical based processes and this paper will describe recent results with chemicals that have been identified as either disinfection by-products, emerging pollutants of concern and/or common ground water contaminants.