Oxidation of pharmaceutical compounds by ozonation and ozone/activated carbon coupling: a kinetic approach

Abstract

The aim of this work was to study the efficiency of ozone (O₃)/activated carbon (AC) coupling to remove metoprolol and fluoxetine. A kinetic study was performed at pH ranging from 3 to 9. Results were correctly modelled by a global first-order model (r² > 0.99) and were compared to those obtained with the ozonation process. It was shown that O₃/AC coupling was the most efficient process. At pH 9, the degradation kinetic constant reached 0.72 min⁻¹ with O₃/AC coupling while its maximum value was 0.34 min⁻¹ with ozonation. In each experimental condition and for the two target compounds, this coupling allowed a fast and total pollutant removal. Moreover, its performances were not significantly influenced by the experimental conditions, contrary to the ozonation process which is strongly influenced by the pH and the nature of the pollutant. O₃/AC coupling remained efficient even if the operational parameters disfavour pollutant oxidation.

Keywords:

• Pharmaceuticals
• Wastewater treatment
• Ozone
• Activated carbon
• Kinetics

Acknowledgements

The authors wish to thank Xavier Bourrain and the Agence de l’Eau Loire Bretagne for their technical and financial support, and Pica Jacobi for gratuitously supplying AC.