Simulating micropollutant abatement during cobalt mediated peroxymonosulfate process by probe-based kinetic models

Abstract

Prediction of micropollutant abatement during advanced oxidation processes by modelling can provide valuable information to optimize the process for efficient water treatment. In this study, a probe-based kinetic model was developed to simulate micropollutant abatement during water treatment by a cobalt-mediated peroxymonosulfate (Co(II)/PMS) process. Eight micropollutants (atrazine, primidone, sulfisoxazole, sulfamethoxypyridazine, gemfibrozil, chloramphenicol, p-chlorobenzoic acid, and perfluorooctanoic acid) were spiked in various water matrices (synthetic water and real surface water), which were then treated by the Co(II)/PMS process. By following the decay of PMS, atrazine, and primidone (as sulfate and hydroxyl radical (SO4·- and ·OH) probes) during the process, the exposures of PMS, SO4·- and ·OH were calculated using the model. Then, based on the determined exposures, the abatement efficiencies of the other micropollutants could be reasonably predicted with the model. The results indicate that by using a couple of probes to measure the SO4·- and ·OH exposures, the model can be used for the generalized prediction of the abatement of various micropollutants during water treatment by the Co(II)/PMS process. In addition, modelling results show that for a given water matrix, the ratios of SO4·- and ·OH concentrations to PMS concentrations (RSP and RHP) are almost constant during the Co(II)/PMS process. This finding allows the transient concentrations of SO4·- and ·OH to be quantified based on the constant RSP and RHP ratios and the PMS concentrations observed during the process. The results of this study suggest that the probe-based kinetic models can provide a useful tool to characterize the persulfate-based process and to predict the abatement efficiencies of various micropollutants during water treatment.