The degradation of municipal solid waste incineration leachate by UV/ persulfate and UV/H2O2 processes: The different selectivity of SO4?- and ?OH

In this work, the different selectivity of SO4 center dot-and center dot OH towards municipal solid waste incineration leachates (MSWILs) was studied by a comparative study of UV/persulfate (PS) and UV/H2O2. Results showed SO4 center dot- pref-erentially mineralized carbon atoms of higher average oxidation state, while center dot OH showed a two-stage mechanism of partial oxidation and mineralization successively. Electron spin resonance (ESR) analysis showed SO4 center dot-had superior selectivity towards MSWILs than center dot OH, and Fe(II) would significantly affect the selectivity via forming Fe-MSWILs complex. As the consequence, Fe(II) showed slightly negative effect on UV/PS, but greatly enhanced the performance of UV/H2O2/Fe(II). High concentration of Cl- affected the degradation of non-fluorescent substances by UV/PS, while SO42- and NO3- showed no effect. In contrast, anions showed no effect on UV/ H2O2. In addition, center dot OH preferentially attacked large molecules, but SO4 center dot-showed no selectivity. This study further revealed the selectivity of SO4 center dot-and center dot OH in the treatment of hypersaline wastewater, and provided theoretical support for the development of targeted technology.