Effective degradation of tetracycline by visible light-assisted activation of persulfate (PDS) by the magnetic material MnFe2O4/BC/P-CN

Abstract

Large amounts of antibiotic residues cause serious damage to the ecological environment and water resources. Traditional treatment techniques have limited ability to remove them. In this paper, the magnetic material MnFe₂O₄/BC/P-CN was successfully prepared using a simple combination of roasting and impregnation strategy. Photofenton degradation of antibiotic pollutant tetracycline was carried out under visible light irradiation using peroxosulfate (K₂S₂O₈) as an oxidizing agent, and the degradation rate reached 99.7 % within 70 min. This was attributed to the synergistic promotional effect between P-CN/BC and MnFe₂O₄, including good adsorption, enhanced light absorption, and high charge carrier mobility. EPR assay showed that the main active substances included •O₂⁻, ¹O₂, •SO₄⁻ and •OH, which was derived from S₂O₈²⁻, which promoted the self-oxidizing reduction of iron and manganese atoms. The materials were found to be structurally stable with excellent performance through multiple recycling. This ternary photocatalyst, composed of three semiconductors with excellent band gaps, is expected to achieve efficient absorption of sunlight. We characterized the P-CN/BC/MnFe₂O₄ photocatalyst through various analytical techniques and investigated its performance in degrading TC under visible light. Additionally, we used methods such as radical detection and intermediate product identification to thoroughly elucidate the mechanism of persulfate activation by photocatalysis and the degradation pathway of tetracycline.