Ozone Decomposition in Aqueous Media

LOVATO MARTÍN CASSANO

Palermo, Italia

Congreso; 5° European Meeting on Solar Chemistry and Photocatalysis: Environmental Applications; 2008

A kinetic scheme for Ozone decomposition in aqueous media has been developed. It can be applied for a significant range of pHs from acidic to neutral operating conditions. All experiments were made in a homogeneous medium under an assured kinetic controlling regime. Under no circumstances a head space existed in the reactor volume. The starting point of the reaction was always under the prerequisite of a true state of initial equilibrium conditions for the mixture Water-Ozone-Oxygen. The model, that is not intended to be a true reaction mechanism, was derived from the 18 reaction steps mechanism proposed by Bühler et al. [1] and Staehelin et al. [2]. With an accurate phenomenological modification represented by an analytical expression, a function of pH was introduced in just one - critical - constant of the previously mentioned mechanistic kinetics. The resulting set of reactions steps reproduces with very good agreement experiments made at pH 3, 4.8 and 6.3. These results should be useful to be applied as background information to analyze the use of Ozone to degrading organic compounds that render reaction intermediates and/or products, which reduce the pH of the reacting medium along the reaction evolution.