Activation of PMS for tetracycline removal by waste-derived FeOOH/Fe3O4 magnetic nanocomposites: Ecotoxicity calculations and mechanism analysis

The development of a low-cost catalytic system using waste copper slag to activate peroxymonosulfate (PMS) for tetracycline (TC) degradation in water represents a green and efficient pathway. In this study, magnetic FeOOH@Fe₃O₄ nanoparticles were synthesized from copper slag and applied in a material/PMS system to degrade TC. Experimental results demonstrated a remarkable 99 % TC removal efficiency within 30 min. Characterization analysis revealed that the amorphous structure of FeOOH promotes the formation of amorphous zones and multiphase interfaces, thereby exposing more active sites and enhancing catalytic activity. This effect, combined with the large specific surface area of Fe₃O₄, significantly accelerated the degradation rate. Notably, the material maintained an 80 % degradation efficiency even after five reuse cycles. The reaction mechanism involves multiple pathways, including free radical and non-free radical mechanisms, as well as adsorption and electron transfer, with the non-radical singlet oxygen ( 1 O₂) being the predominant reactive species. Furthermore, the study proposes potential degradation intermediates and outlines possible degradation pathways for TC, while also predicting associated toxicity changes. This research provides a novel methodology for developing environmental functional materials from solid waste, offering valuable insights for addressing the dual challenges of waste disposal and the degradation of emerging pollutants. • Successful synthesis of slag-derived FeOOH@Fe 3 O 4 magnetic nanocatalysts. • The influencing factors of oxidative degradation of TC were evaluated. • The catalytic mechanism and degradation pathways of FeOOH@Fe 3 O 4 /PMS were proposed. • The ecotoxicity of TC and degradation intermediates was investigated.