Kinetics Of Natural Organic Matter As The Initiator, Promoter And Inhibitor In Water Ozonation And Its Influences On The Removal Of Ibuprofen.

Abstract

Natural organic matter (NOM) can simultaneously react as the initiator, promoter and inhibitor in hydroxyl radical (?OH) chain reactions in water ozonation. The rate constants of NOM in these reactions, however, have never been quantified due to their complexity. This results in difficulties to quantitatively describe the influences of NOM on the degradation of organic pollutants, such as pharmaceutical compounds, by ozonation. The aims of this study were to develop a new method to quantify these different reaction rate constants of NOM in water ozonation and to study their influences on the removal of ibuprofen, a commonly detected pharmaceutical compound in surface water. In this study, a new method integrating the transient steady-state ?OH model, the Rct concept and the pseudo first-order ozone decomposition model that can be used to determine the different rate constants of NOM was developed. This method was first validated using simple model compounds that are representative of the initiator, promoter and inhibitor followed by its applications to three NOM isolates and a natural water. The determined rate constants of NOM were used to quantitatively describe the influences of NOM on the removal of ibuprofen in the presence of carbonate alkalinity.