Elucidating the enhanced role of carbonate radical in propranolol degradation by UV/peroxymonosulfate system.

Carbonate radical (CO ₃ ^•- ) has been proved to be an important secondary radical in advanced oxidation processes due to various radical reactions involved HCO ₃ ^- /CO ₃ ^2- . However, the roles and contributions of CO ₃ ^•- in organic micropollutant degradation have not been explored systematically. Here, we quantified the impact of CO ₃ ^•- on the degradation kinetics of propranolol, a representative pollutant in the UV/peroxymonosulfate (PMS) system, by constructing a steady-state radical model. Substantially, the measured values were coincident with the predictive values, and the contributions of CO ₃ ^•- on propranolol degradation were the water matrix-dependent. Propranolol degradation increased by 130% in UV/PMS system containing 10 mM HCO ₃ ^- , and the contribution of CO ₃ ^•- was as high as 58%. Relatively high pH values are beneficial for propranolol degradation in pure water containing HCO ₃ ^- , and the contributions of CO ₃ ^•- also enhanced, while an inverse phenomenon was shown for the effects of propranolol concentrations. Dissolved organic matter exhibited significant scavenging effects on HO ^• , SO ₄ ^•- , and CO ₃ ^•- , substantially retarding the elimination process. The developed model successfully predicted oxidation degradation kinetics of propranolol in actual sewage, and CO ₃ ^•- contribution was up to 93%, which in indicative of the important role of CO ₃ ^•- in organic micropollutant removal via AOPs treatment.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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