Synthesis of Cu/Mn/Ce polymetallic oxide catalysts and catalytic ozone treatment of wastewater

Non-homogeneous ozone-catalyzed oxidation technology is one of the effective ways of treating wastewater, the core of which lies in the development of efficient ozone oxidation catalysts. This work proposes the design and synthesis of an efficient Cu/Mn/Ce multi-metal composite oxide catalyst by metal salt precursor mixing-direct granulation. The effect of metal doping on the catalyst properties was compared using Density function theory (DFT) calculations, and the Cu/Mn/Ce co-doping showed significant charge accumulation effect with a low ozonolysis energy barrier, which is more favorable for the generation of reactive oxygen species. The successful loading of the main active metal components, such as Mn, Cu, and Ce, was clarified by systematic characterization by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Brunauer–Emmett–Teller's test (BET), and the chemical oxygen demand (COD) removal could reach more than 60% for the simulated wastewater. The electron paramagnetic resonance (EPR) characterization clarified that the degradation of organic pollutants was mainly dominated by the combination of single-linear oxygen and superoxide radicals in the catalytic process, and the possible catalytic oxidation mechanism was proposed. This work advances the development of non-homogeneous ozone oxidation technology.