Generation and intensity of active oxygen species in thermally activated persulfate systems for the degradation of trichloroethylene

Abstract

The degradation of trichloroethylene (TCE) was evaluated in a thermally activated persulfate system and the generation of active oxygen species investigated using various probe compounds. The experimental results showed that TCE was completely degraded in 9 min at 50 °C with an initial TCE concentration of 0.15 mM and a dose of 0.3 M persulfate. The influence of the solution matrix on the degradation of TCE was evaluated and it was shown that concentrations of 100 mM Cl−, 10 mM HCO3− and 100 mg L−1 humic acid (HA) affect the degradation of TCE. In addition, tests investigating the effects of Cl−, HCO3− and HA on the generation and intensity of active oxygen species showed that HCO3− affected the degradation of TCE by decreasing the intensities of ˙SO4− and ˙OH, while increasing the intensity of ˙O2−. In contrast, Cl− and HA influenced the degradation of TCE by decreasing the intensities of ˙OH and ˙O2− while increasing the intensity of ˙SO4−. The results from this study provide a key foundation for further studies of the remediation of groundwater contaminated by chlorinated solvents using the thermally activated persulfate process.