Insights into multi-pathway peroxymonosulfate activation by copper-doped Ca/Mn perovskite oxides for diethyl phthalate degradation

Peroxymonosulfate (PMS) activation based on metallic catalysts with versatile mineral structures and superior catalytic properties has attracted much attention. In this study, we built a CaMnO3(CMO) with copper dopped to promote PMS activation by Mn(III)/Mn(IV) and Cu(I)/Cu(II) redox cycles with the synergistic effect of bimetal for efficient degradation of diethyl phthalate (DEP). Under optimal conditions, 95.7% of DEP (10 mg L−1) degradation was realized in 60 min, and the mineralization reached 75%, while only 26.9% of DEP was removed with little TOC removal by CaMnO3. Unexpectedly, not only •OH, O2•− and SO4•−, but also nonradical pathway singlet oxygen (1O2) was found to be involved in the CMO-Cu/PMS system. The redox cycles of Mn(III)/Mn(IV) and Cu(I)/Cu(II) effectively promoted PMS activation to reactive oxygen species (ROS), which were responsible for DEP degradation. Furthermore, density functional theory (DFT) calculations and liquid chromatograph-mass spectrometer (LCMS) were combined to explore the degradation pathway. This work provides a new insight for developing heterogeneous perovskites for PMS activation to construct more efficient method for water treatment.