Activation of peroxymonosulfate by CuO-OMS-2 for efficient phenol mineralization: performance, contributions of ROS, and catalytic mechanisms

In this paper, copper oxide supported manganese oxide octahedral molecular sieves (CuO-OMS-2) composite was successfully synthesized and subsequently investigated for the degradation and mineralization of phenol via peroxymonosulfate (PMS) activation. It was confirmed that the incorporation of CuO significantly promoted multivalent metals transition and oxygen vacancies generation. At initial pH 5.0, CuO-OMS-2 achieved the optimum catalytic activity with 93.6% of phenol degradation efficiency and 87.6% of mineralization rate in 30 min. Additionally, a probe-based kinetic model was developed to simulate the removal of phenol in CuO-OMS-2/PMS system under different pH conditions, which was a decisive factor to affect the transformation of main active radicals and the oxidation capacity. The quantitative results of the active radicals suggested that ¹O₂ and O₂^•− played generally a negligible role in the abatement of phenol, while the contribution of SO₄^•− gradually increased from 25.17 to 75.60% and that of ^•OH decreased from 69.23 to 22.80% with the rising of pH from 3 to 9. Meanwhile, the CuO-OMS-2 composite showed excellent stability and reusability for contaminant degradation during five consecutive cycles. Finally, the results of probe-based kinetic model and characterization jointly demonstrated the mechanism of phenol degradation by CuO-OMS-2 activating PMS.

Graphical abstract