A KINETIC-MODEL OF THE HYDROGEN-PEROXIDE UV PROCESS FOR THE TREATMENTOF HAZARDOUS-WASTE CHEMICALS

The effectiveness of the H2O2/UV process has been investigated using t richloroethylene (TCF), tetrachloroethylene (PCE), benzene, and toluen e as model compounds. The UV source used in this study was the low pre ssure mercury vapor lamp using mainly 254 nm of radiation. For irradia tion of aromatic compounds such as benzene and toluene at high concent ration, by-products formed by the irradiation process were found to re duce the oxidation rate; these by-products also acted as UV absorbers in competition with the parent compounds. A kinetic model for the rate of direct photolysis of organics has been developed illustrating a me thod of measuring quantum yields of photolysis in the presence of by-p roducts. It was also found that the addition of peroxide enhanced the oxidation rate. The enhancement rate of TCE was greater than that of b enzene even though k(benzene,OH) is greater than k(TCE,OH). The overal l rate of the H2O2/UV system was found to depend on the relative impor tance of the OH radical pathway, the direct photolysis reaction rate, and the absorptivity of by-products at 254 nm.