In situ enhanced catalytic degradation behavior of antibiotics by graphite anodes from spent lithium-ion batteries: The unique role of self-doped metals

Abstract

The research on recycling secondary resources and addressing emerging pollutants has earned global interest. In this study, we recycled spent graphite (SG) from retired lithium-ion batteries (LIBs) and prepared graphite catalyst (PMG) via pyrolysis and mechanical activation for tetracycline hydrochloride (TC) adsorption. The carbon materials were characterized by various analysis methods, which illustrated SG contained self-doped metals (SDMs) like Cu, Fe, and synthesized PMG had an extensive specific surface area (237.2 m²/g). These unique properties made PMG a highly potential catalyst for aqueous antibiotics contamination. The results showed the rapid degradation of TC (2 min, 98.3%) with 0.5 vol% H₂O₂ and 250 mg/L TC and high adsorption capacity (495 mg/g) highlighted the exceptional catalytic activity of the PMG, mainly attributed to SDMs. Through studies of the mechanism, we found that TC degradation was driven by generated free radicals and singlet oxygen, with •O₂⁻/HO₂• radicals playing a dominant role.