Oxidation of PAHs in water solution by ozone combined with ultraviolet radiation

Abstract

The oxidation of three polycyclic aromatic hydrocarbons (PAHs): benzo[a]pyrene (BAP), chrysene (CHR) and fluorene (FLU) in aqueous solution using ozone assisted by UV radiation was investigated. The influence of pH of the reaction mixture, ozone concentration and the presence of a radical scavenger on the reaction rate was determined. The highest rate of PAHs disappearance was achieved in acidic solutions. The radical scavenger-tert- butanol, effectively inhibited the rate of BAP and CHR destruction but had a slight influence in the case of FLU. The rate constants of direct reaction of PAHs with ozone were calculated using our earlier investigations and they were equal to 6.8 × 104; 6.9 × 103 and 62M -1s-1 for BAP, CHR and FLU, respectively. The contributions of direct ozonolysis, photolysis and radical reaction to PAHs oxidation in O3/UV system were evaluated.