Highly efficient removal and detoxification of phenolic compounds using persulfate activated by MnO x @OMC: Synergistic mechanism and kinetic analysis.

Persulfate-based advanced oxidation technology exhibits great potential for hazardous organic pollutant removal from wastewater. Acceleration of pollutant degradation needs to be elucidated, particularly for heterogeneous catalytic systems. In this study, manganese oxide ordered mesoporous carbon composites (MnO _x @OMC) were prepared by nano-casting method and used for persulfate activation to degrade phenol. Kinetics analysis indicate that the rate of phenol degradation using MnO _x @OMC composites was improved by 34.9 folds relative to that using a mixture of MnO _x and OMC. The phenol toxicity towards Caenorhabditis elegans could be totally reduced within 8 min. The different roles of MnO _x and OMC in persulfate activation were confirmed to validate their synergistic effect. MnO _x provided major active sites for persulfate activation in accordance with the surface Mn ³⁺ /Mn ⁴⁺ cycle to induce SO ₄ ^•- radicals. The OMC matrix provided the adsorption sites to enrich phenol molecules on the catalytic surface and promote the interfacial electron transfer process for persulfate activation. Moreover, a novel kinetic model with two distinct kinetic stages was established to verify the effects of phenol and persulfate on phenol removal.
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