Chemical models of advanced oxidation processes

Advanced oxidation processes (AOPs) have been defined as near-ambient temperature processes that involve the generation of highly reactive radical intermediates, especially the hydroxyl radical. These processes show promise for the destruction of hazardous organic substances in municipal and industrial wastes, in drinking water and in ultrapure water. Three types of AOPs are considered in this paper: catalyzed decomposition of ozone; ozone with hydrogen peroxide (Peroxone); and photolysis of hydrogen peroxide with ultraviolet radiation. Kinetic models for these processes are being developed based on known chemical and photochemical principles. The models take into account measured effects of radical scavengers such as bicarbonate; dose ratios of the oxidants or UV intensity; pH; and the presence of generic radical scavengers. The models are used to discuss two cases: oxidation of parts-per-million levels of nitrobenzene with ozone, Peroxone and peroxide/UV and oxidation of naphthalene and pentachlorophenol with peroxide/UV.