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[Display omitted] • Sulfated solid superacid SO 4 2–/Fe 2 O 3 -CuO was synthesized for catalytic ozonation. • Internal electron transfer capability and cycling of Fe(III)/Fe(II) and Cu(II)/Cu(I). • Abundant Lewis acid sites on surface facilitated the catalytic decomposition of O 3. • The main active species were OH, O 2 −, and 1O 2. • High applicability for cyclic compounds removal in bio-treated coking wastewater. In wastewater treatment, the degradation of refractory cyclic compounds by catalytic ozonation using sulfated solid superacid has not been thoroughly investigated. The doped S element alters the electronic activity and drives the ozone oxidation of recalcitrant organic pollutants, potentially leading to an increase in catalytic efficiency. This study aimed to develop a novel iron-copper sulfate (SO 4 2–/Fe 2 O 3 -CuO) solid superacid composite to strengthen catalytic reactions. According to the characterization results, the embedding of SO 4 2– enhanced the electron transfer inside the material, leading to more Lewis acid sites, which facilitated the catalytic decomposition of O 3. The catalytic degradation and reaction kinetics experiments on quinoline verified the superior catalytic performance of the SO 4 2–/Fe 2 O 3 -CuO system compared to other systems. Fluorescence, UV–Vis spectrophotometry, and EPR experiments demonstrated that the hydroxyl radicals (OH), superoxide radicals (O 2 −), and singlet oxygen (1O 2) were generated in the SO 4 2–/Fe 2 O 3 -CuO system, and their presence accelerated the redox cycling of Fe(III)/Fe(II) and Cu(II)/Cu(I). In addition, the possible degradation pathways of quinoline were verified by density functional theory (DFT) calculations, and the toxicity of intermediates was assessed by quantitative structure–activity relationship (QSAR) analysis. Finally, the applicability of the SO 4 2–/Fe 2 O 3 -CuO catalytic system in bio-treated coking wastewater (BTCW) was validated. GC–MS experiments further confirmed that it was mainly the cyclic compounds that contributed to the removal rate during the catalytic process. In summary, this study demonstrated the significant potential of the SO 4 2–/Fe 2 O 3 -CuO catalytic system in degrading refractory cyclic compounds, providing valuable technical support for the field of wastewater treatment. [ABSTRACT FROM AUTHOR]

The Co/Ni-MOFs@CS composite derived from Co/Ni bimetallic organic framework was synthesized and characterized. Compared with a single O 3 system, the synergy between carbon sphere (CS) and metal organic frameworks (MOFs) improved the electron transfer efficiency and the formation rate of •OH. The coexistence of Co and Ni in various valence states might accelerate the cyclic process of Co(II)/Co(III) and Ni(II)/Ni(III), thereby improving the catalytic activity. Taking levofloxacin as a model pollutant, the mechanism of catalytic process was discussed, and the catalytic reaction was successfully applied to the removal of residual organics in bio-treated coking wastewater (BTCW). The removal rates of chemical oxygen demand (COD) and total organic carbon (TOC) in 60 min were 50.85%–53.71% and 39.98%–43.48%. From the perspective of UV absorption and 3D EEM, catalytic ozonation was more conducive to breaking the electronic protection of inert organic molecules such as heterocyclic compounds, and achieving higher efficiency of mineralization. It provides a new idea for catalytic ozonation technology of wastewater treatment in the future from theory, technology and application. [Display omitted] • The Co/Ni-MOFs@CS was successfully synthesized by hydrothermal method. • High specific surface areas and coexistence of multiple valence metals. • Strong nonselective oxidation capacity of OH was the mian factor for mineralization. • From the mineralization of single organic pollutant to the application of BTCW. [ABSTRACT FROM AUTHOR]

The Co/Ni-MOFs@CS composite derived from Co/Ni bimetallic organic framework was synthesized and characterized. Compared with a single O 3 system, the synergy between carbon sphere (CS) and metal organic frameworks (MOFs) improved the electron transfer efficiency and the formation rate of •OH. The coexistence of Co and Ni in various valence states might accelerate the cyclic process of Co(II)/Co(III) and Ni(II)/Ni(III), thereby improving the catalytic activity. Taking levofloxacin as a model pollutant, the mechanism of catalytic process was discussed, and the catalytic reaction was successfully applied to the removal of residual organics in bio-treated coking wastewater (BTCW). The removal rates of chemical oxygen demand (COD) and total organic carbon (TOC) in 60 min were 50.85%–53.71% and 39.98%–43.48%. From the perspective of UV absorption and 3D EEM, catalytic ozonation was more conducive to breaking the electronic protection of inert organic molecules such as heterocyclic compounds, and achieving higher efficiency of mineralization. It provides a new idea for catalytic ozonation technology of wastewater treatment in the future from theory, technology and application. [Display omitted] • The Co/Ni-MOFs@CS was successfully synthesized by hydrothermal method. • High specific surface areas and coexistence of multiple valence metals. • Strong nonselective oxidation capacity of OH was the mian factor for mineralization. • From the mineralization of single organic pollutant to the application of BTCW. [ABSTRACT FROM AUTHOR]