Activation of peroxymonosulfate with cobalt embedded in layered δ-MnO2 for degradation of dimethyl phthalate: Mechanisms, degradation pathway, and DFT calculation.

The sulfate radical-based advanced oxidation processes (SR-AOPs) offer huge potential for the removal of organic pollutants. In this study, Co(II)-intercalated δ-MnO2 (Co-δ-MnO2) catalyst was successfully prepared by a simple cation exchange reaction. The obtained Co-δ-MnO2 exhibited high catalytic performance for the removal of dimethyl phthalate (DMP) under the activation of peroxymonosulfate (PMS), with the degradation efficiency reaching 100% within 6 h. Experiments and theoretical calculations revealed that interlayer Co(II) provided unique active sites in Co-δ-MnO2. In addition, radical and non-radical pathways were confirmed to play a role in Co-δ-MnO2/PMS system. •OH, SO4• ̶, and 1O2 were identified to be the dominating reactive species in Co-δ-MnO2/PMS system. This study provided new insights into the design of catalysts and laid a foundation for developing modifiable layered heterogeneous catalysts.