Abstract: | As a green oxidant, permanganate has received considerable attention for the removal of micropollutants in drinking water
treatment. To provide a better understanding of the oxidation of organic micropollutants with permanganate, the oxidation
kinetics of 32 micropollutants were compiled. The pollutants include algal toxins, endocrine disrupting chemicals (EDCs),
and pharmaceuticals. The oxidation kinetics of micropollutants by permanganate were found to be first order with respect to
both contaminant and permanganate concentrations from which second-order rate constants (k″) were obtained. Permanganate oxidized the heterocyclic aromatics with vinyl moiety (i.e., microcystins, carbamazepine, and
dichlorvos) by the addition of double bonds. For the polycyclic aromatic hydrocarbons (PAHs) with alkyl groups, permanganate
attacked the benzylic C-H through abstraction of hydrogen. The mechanism for the oxidation of phenolic EDCs by permanganate
was a single electron transfer and aromatic ring cleavage. The presence of background matrices could enhance the oxidation
of some phenolic EDCs by permanganate, including phenol, chlorinated phenols, bisphenol A, and trichlosan. The toxicity of
dichlorvos solution increased after permanganate oxidation, and the estrogenic activity of bisphnol A/estrone increased significantly
at the beginning of permanganate oxidation. Therefore, the toxicity of degradation products or intermediates should be determined
in the permanganate oxidation processes to better evaluate the applicability of permanganate. The influence of background
ions on the permanganate oxidation process is far from clear and should be elucidated in the future studies to better predict
the performance of permanganate oxidation of micropollutants. Moreover, methods should be employed to catalyze the permanganate
oxidation process to achieve better removal of micropollutants. |