Comparative study of chloroquine phosphate degradation by calcite/PMS and dolomite/PMS systems

Advanced oxidation processes employing natural carbonate minerals to activate peroxymonosulfate (PMS) have exhibited remarkable efficacy in the removal of organic pollutants. In this study, the differences in the degradation performance and mechanism of chloroquine phosphate (CQP) by calcite/PMS and dolomite/PMS systems were investigated. Experimental findings reveal that the calcite/PMS system demonstrates markedly superior removal under identical conditions, achieving 99 % CQP removal within 60 min. In contrast, the dolomite/PMS system only achieved 63 % CQP removal under the same conditions. Electron paramagnetic resonance (EPR) and radical quenching analyses identified singlet oxygen ( 1 O 2 ) as the dominant reactive species in both systems. Quantitative assessments indicated that the calcite/PMS system generated more 1 O 2 (43.3 μM) compared to the dolomite/PMS system (35.4 μM.). This phenomenon was attributed to that calcite released more carbonate ions (CO 3 2− ) than dolomite. Although the two systems had different reaction rates, both achieved stable CQP removal over 90 % in a one-month continuous flow column experiments. This work developed the application potential of carbonate minerals in advanced oxidation systems. Furthermore, the findings contribute to better understanding and development of carbonate activated persulfate systems.