Experimental aspects of mechanistic studies on aqueous ozone decompositionin alkaline solution

Ozone decomposition in aqueous solution was studied by the stopped flow met hod over the pH 10.4 - 13.2 range at 25 +/- 0.1 degrees C and I = 0.5 M NaC lO4. At 260 nm the molar absorptivity of aqueous ozone was determined to be 3135 +/- 22 M(-1)cm(-1). It was shown that various experimental factors ma y significantly alter the course of the reaction. Even small amounts of H2O 2 absorbed by the plastic parts of the stopped-flow instrument can affect t he kinetic features of the reaction for an extended period of time. Under s trictly controlled experimental conditions sufficiently reproducible data c ould be obtained for the decomposition. The data were evaluated by comparin g experimental and simulated kinetic traces. A detailed kinetic model was d eveloped which is able to predict the decay and life-time of ozone as well as the formation and decomposition of the ozonide ion radical (O-3(-)) over the pH 10.4 - 13.2 range.