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

Abstract

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.