Efficient degradation of organic pollutants by ozone oxidation catalyzed by chitosan-derived N-doped carbon and MnFe2O4 co-doped CuS.

The presence of dyes in wastewater can cause serious harm to aquatic organisms and humans. In this paper, the magnetic composite, chitosan-derived N-doped carbon (NCS) and MnFe2O4 co-doped CuS (MFO/NCS@CuS) was successfully prepared by hydrothermal-solvothermal method to catalyze ozone degradation of methylene blue (MB). The composite catalyst was characterized by XRD, FT-IR, SEM, VSM and XPS. The results showed that a large number of active sites were exposed on CuS supported NCS. CuS supported NCS not only dispersed MnFe2O4 nanoparticles and improved the stability of the catalyst, but also provided rich electron-rich groups for the catalytic process and improved the catalytic efficiency. MFO/NCS@CuS/O3 degraded MB (50 mg/L) by 98.14 % in 12 min, and degraded MO, RhB and TC (20 mg/L) by above 90 %. As an ozone catalyst, MFO/NCS@CuS showed good anti-interference, universality, stability, environmental friendliness and catalytic performance. Cu+/Mn2+/Fe2+ was the main catalytic active centers. S2- and Sn2- promoted the electron transfer between the redox cycles of Cu2+/Cu+, Mn3+/Mn2+ and Fe3+/Fe2+. The results of this work provide a new idea for the study of heterogeneous ozone catalysis.