Catalytic performance and periodate activation mechanism of anaerobic sewage sludge-derived biochar

Periodate (PI)-based advanced oxidation processes are a newly discovered approach for effective pollutant elimination. In this study, we demonstrated that biochar obtained from pyrolysis of anaerobic sewage sludge without any pretreatment can be used for PI activation. The biochar obtained at 800 degrees C (SBC-800) exhibited the best PI activation capacity using acid organic II (AO7) as substrate. The PI activation was strongly dependent on pH and exhibited the highest AO7 removal rate at pH 3.0. Meanwhile, the anti-interference capacity with common wastewater components and reusability of the SBC-800/PI system were confirmed. Combined with the results of chemical quenching, reactive oxygen species (ROS) trapping, X-ray photoelectric spectroscopy (XPS), electrochemical and density function theory (DFT)-based calculations, singlet oxygen production and electron transfer mediated by the SBC-800-PI complex were the dominant AO7 oxidation mechanisms. This study provides easily prepared catalysts for PI activation and paves the way for solid waste recycling and reuse.

Automated summary

Biochar obtained from pyrolysis of anaerobic sewage sludge without pretreatment can be effectively used for PI activation, with the best activation achieved at 800 degrees C. The activation of PI is highly pH-dependent, showing the highest AO7 removal rate at pH 3.0. The SBC-800/PI system has demonstrated anti-interference capacity with common wastewater components and can be reused, with singlet oxygen production and electron transfer being the dominant AO7 oxidation mechanisms.