Acceleration of Fenton-like Reaction by Bimetal-Mediated\nSludge Biochar for Tetracycline Removal

The\nproduction of sludge biochar (SBC) from residual sludge offers\na solution to the challenges associated with sludge disposal and facilitates\nthe reutilization of resources. In the present research, a bimetallic-modified\nsludge biochar, designated as FeCu-SBC, was synthesized by varying\nthe doping ratios of FeSO<sub>4</sub> and CuSO<sub>4</sub>. This material\nwas intended for the effective degradation of tetracycline (TC) in\naqueous environments via the activation of peroxydisulfate. The FeCu2-SBC\n(90% degradation rate) composite, synthesized through the incorporation\nof Fe and Cu in a 1:2 ratio with SBC, exhibited a degradation rate\nof TC, which was 2.7 times higher than that of SBC (32.85% degradation\nrate) and 1.8 times higher than that of FeCu (50% degradation rate).\nResearch examining the mechanisms involved revealed that FeCu underwent\ndegradation solely through the radical (<sup>•</sup>OH) pathway,\nwhereas FeCu2-SBC was subject to degradation through both radical\n(SO<sub>4</sub><sup>•–</sup>) and nonradical (<sup>1</sup>O<sub>2</sub>) pathways. This phenomenon was attributed to the distinct\nπ–π, CO, and defect structures in FeCu2-SBC\ncompared to FeCu, which facilitated the activation process leading\nto the production of reactive species. This investigation presented\na cost-effective approach for producing bimetallic-modified sludge\nbiochar, offering perspectives on determining the crucial elements\ninfluencing the streamlined TC degradation pathway.