Acceleration of Fenton-like Reaction by Bimetal-Mediated Sludge Biochar for Tetracycline Removal.

The production of sludge biochar (SBC) from residual sludge offers a solution to the challenges associated with sludge disposal and facilitates the reutilization of resources. In the present research, a bimetallic-modified sludge biochar, designated as FeCu-SBC, was synthesized by varying the doping ratios of FeSO and CuSO. This material was intended for the effective degradation of tetracycline (TC) in aqueous environments via the activation of peroxydisulfate. The FeCu2-SBC (90% degradation rate) composite, synthesized through the incorporation of Fe and Cu in a 1:2 ratio with SBC, exhibited a degradation rate of TC, which was 2.7 times higher than that of SBC (32.85% degradation rate) and 1.8 times higher than that of FeCu (50% degradation rate). Research examining the mechanisms involved revealed that FeCu underwent degradation solely through the radical (OH) pathway, whereas FeCu2-SBC was subject to degradation through both radical (SO) and nonradical (O) pathways. This phenomenon was attributed to the distinct π-π, C═O, and defect structures in FeCu2-SBC compared to FeCu, which facilitated the activation process leading to the production of reactive species. This investigation presented a cost-effective approach for producing bimetallic-modified sludge biochar, offering perspectives on determining the crucial elements influencing the streamlined TC degradation pathway.