Synergistic effect of the combination of immobilized TiO₂, UVA and ozone on the decomposition of dichloroacetic acid

Abstract

The performance of a heterogeneous photocatalytic ozonation system (TiO₂/UVA/O₃) was evaluated on the degradation and mineralization of dichloroacetic acid as a contaminant in aqueous solutions by means of a planar reactor. The commercial product “Pilkington Active^TM glass” was used as the immobilized TiO₂ photocatalyst and it was irradiated by near UV light in this study. The synergistic interaction between ozone and the photoactivated TiO₂ surface was discussed and highlighted. Furthermore, the influences of initial concentration and temperature on the degradation rate of dichloroacetic acid and the ozone consumption level during the oxidation process were investigated. The concentrations of dichloroacetic acid and chloride anions produced during degradation were measured using ion chromatography. The mineralization of dichloroacetic acid was evaluated by Total Organic Carbon (TOC) measurements. The degradation of dichloroacetic acid by photocatalytic ozonation showed good agreement with the kinetics of first-order reactions with respect to dichloroacetic acid.

Keywords:

• Photocatalytic ozonation
• advanced oxidation processes (AOPs)
• dichloroacetic acid (DCAA)
• TiO₂
• Pilkington Active^TM
• water treatment

Acknowledgments

This work was supported financially by the chair of Atmospheric Chemistry and Air pollution Control, Brandenburg University of Technology (BTU Cottbus) and INU (Institute für nachhaltigen Umweltschutz).