ABSTRACT
Ozone reactions in water and wastewater are heterogeneous parallel-series gas liquid reactions in which a gas component (ozone) transfers from the gas phase (oxygen or air) to the water phase where it simultaneously reacts with other substances (pollutants) while diffusing. The main aim of the kinetic study is to determine the rate constant of the reactions and mass transfer coefficients. This is achieved by establishing the corresponding kinetic law.1 In contrast to chemical equilibrium, kinetic laws are empirical and must be determined from experiments. According to the type of experiments, the ozonation kinetic study can follow one of two different approaches. The first approach is based on experimental results of homogeneous ozonation reactions. This is the case where ozone and any compound are dissolved in water and then mixed and their concentrations with time are observed. The kinetic law, in this case, relates the chemical reaction rate to the concentration of reactants (and products, in the case of reversible reactions). Thus, for any general irreversible ozone direct reaction with a compound B,
(3.1)
and zO3, zB, and zP are the stoichiometric coefficients of ozone, B and P, respectively. The kinetic law corresponding to the ozone or B chemical reaction rates are
(3.2)
and
(3.3)
where k, n, and m are the reaction rate constant and reaction orders for ozone and B, respectively. Note that zO3 and zB have negative values due to convention. Both equations are related by the stoichiometric coefficients
(3.4)
z O z B z PO B P3 3 : ;<
r z kC CO O O n
r z kC CB B O n
r z
z r
z rO
3 1? ?
