Preparation of high oxygen vacancies catalyst CeO2/Al2O3-SiC and its mechanism in enhancing the catalytic ozonation of organic pollutants in coal chemical wastewater

The complete harmless treatment of aromatic organic compounds in coal chemical wastewater (CCW) has always been a big challenge in water process engineering. This study addresses the issue by designing and preparing a kind of Ce and Al bimetallic catalyst with high oxygen vacancies (OVs) based on SiC carrier. The results showed that CeO 2 and Al 2 O 3 were uniformly dispersed on SiC, and the composite material exhibited an ordered cubic structure. The degradation efficiency and enhancement mechanism of the catalyst with ozone oxidation were investigated. When applied to actual CCW with a chemical oxygen demand (COD) concentration exceeding 600 mg/L, the synergy between O 3 and CeO 2 /Al 2 O 3 -SiC increased the degradation efficiency of phenols from 50 % to 99 % and COD from 42 % to 78 % compared to using O 3 alone. CeO 2 /Al 2 O 3 -SiC had a high concentration of oxygen vacancies (OVs = 48.57 %). Further research indicated that oxygen vacancies (OVs) were the main active sites for ozone adsorption and reactive oxygen species (ROSs) generation. Electron paramagnetic resonance (EPR) and quenching experiments also confirmed that O 3 , •O 2 −1 , 1 O 2 were the main active oxidation factors, rather than •OH. Additionally, even after granulating the catalyst, it still achieved 99 % degradation of phenols. Therefore, this study provides theoretical support for the complete harmless treatment of CCW and has broad prospects for industrial application.