Activation of peroxymonosulfate by biochar-supported Fe3O4 derived from oily sludge to enhance the oxidative degradation of tetracycline hydrochloride

• Published in: Journal of environmental management 2023-12, Vol.347, p.119187-119187, Article 119187
• Main Authors: Zhao, Zhenqing, Zhai, Xiaopeng, Shao, Weizhen, Bo, Hongqing, Xu, Lijie, Guo, He, Zhang, Ming, Qiao, Weichuan
• Format: Article
• Language: English
• Subjects: Advanced oxidation processes; Carbon materials; Degradation; Oily sludge; Peroxymonosulfate; Tetracycline hydrochloride
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2023.119187

Carbon materials used for catalysis in advanced oxidation processes tend to be obtained from cheap and readily available raw materials. We constructed a carbon material, OSC@Fe3O4, by loading Fe3O4 onto the pyrolyzed hazardous waste oily sludge. OSC@Fe3O4 was then used to activate peroxymonosulfate (PMS) for the removal of tetracycline hydrochloride (TTCH) from water. At 298 K, 0.2 g⋅L−1 of catalyst and 0.3 g⋅L−1 of PMS, the reaction rate constant of the OSC@I-2/PMS system reached 0.079 min−1, with a TTCH removal efficiency of 92.6%. The degradation efficiency of TTCH remained at 81% after five cycles. The specific surface area and pore volume of OSC@I-2 were 263.9 m2⋅g−1 and 0.42 cm3⋅g−1, respectively, which improved the porous structure of the carbon material and provided more active points, thus improving the catalytic performance. N and S were doped into the oily sludge carbon due to the presence of N- and S-containing compounds in the raw oily sludge. N and S doping led to more electron-rich sites with higher negative charges in OSC@I-2 and gave the oily sludge carbon a higher affinity to PMS, thereby promoting its ability to activate PMS. Sulfate radicals (SO4•‾) played a dominant role in the degradation of TTCH, with demethylation and the breaking of double bonds being a possible degradation pathway. A biotoxicity test showed that the microbial toxicity of the degradation intermediates was significantly reduced. This work provides a strategy for the application of PMS-based catalysts derived from waste carbon resources. •Oil sludge could be pyrolyzed to prepare a carbon material OSC@Fe3O4 for activating PMS.•OSC@Fe3O4 catalyst showed a high performance of TTCH degradation.•Radical pathway (SO4.•‾) played an important role for TTCH degradation by OSC@Fe3O4•Doping of S and N in the OSC improved the catalytic performance of OSC@Fe3O4.