Efficient catalytic ozonation via Mn-loaded C-SiO2 Framework for advanced wastewater treatment: Reactive oxygen species evolution and catalytic mechanism

Heterogeneous catalytic ozonation (HCO) is attractive for water decontamination and catalyst is a core element. How -ever, it is difficult to maintain high efficiency and stability of catalysts under stern conditions. In this study, we pro-posed Mn-loaded C-SiO2-Framework (Mn-CSF) which contained stable silica core and robust carbon shell for efficient catalytic ozonation. The pseudo-first-order kinetic rate constant for oxalic acid removal of Mn-CSF catalytic ozonation was 160 % and 875 % higher than those of Mn-SiO2 and pristine CSF, respectively. Mn-CSF was also proven effective in gasification wastewater treatment, where the COD was decreased to 46 mg center dot L-1, 37 % lower than that of Mn-SiO2. These results indicated that the graphitization carbon layer and Mn significantly enhanced the activity of the catalyst. Furthermore, a fulvic-like component and a protein-like component were recognized through 3D-EEM in coal gasification wastewater. It was proven that Mn-CSF catalytic ozonation exhibited higher fulvic-like component and protein-like component removal compared with ozonation. Moreover, center dot O2- and 1O2 were identified to be respon-sible for organic degradation in this research. Sufficient external specific surface area and porous structure were impor-tant for complex wastewater treatment. Specifically, external specific surface area could enhance the degradation of macromolecular organics while porous structures were vital for smaller molecular pollutant removal. The results high-lighted that Mn-CSF was a promising HCO catalyst for advanced wastewater treatment, and this study provided evi-dence of relationship between structure of catalysts and HCO efficiency.