KINETICS OF BROMACIL OZONOLYSIS

Chemical oxidation processes have been used successfully in the degrad ation of organic pollutants, yet information is limited concerning the kinetic descriptions of the reaction mechanisms. In this study, the k inetics of bromacil (5-bromo-3-sec-butyl-6-methyluracil, a herbicide) ozonolysis was examined. From laboratory observations, a mechanism was proposed by which direct ozone attack occurred and the degradation pa thway proceeded via two parallel reactions. The program MLAB was used to provide a numerical solution for the system of differential equatio ns that described the mechanism. Rate parameters were determined using the slowest reaction system (H2O2/O-3). The kinetic model was then te sted on a system with only bromacil and on a system containing a radic al scavenger. This mathematical model is reasonably consistent with th e experimental observations that the addition of hydrogen peroxide sig nificantly reduces the formation of the byproduct responsible for the residual phytotoxicity of the waste stream.