Shaddock peels biochar doping with Fe-Co bimetal for peroxymonosulfate activation on the degradation of tetracycline: The influence of HCO3− and PO43−

Abstract

To reduce the negative impact of antibiotics on the water environment, shaddock peels biochar co-doped with iron and cobalt (Fe-Co@SPC) was employed in the peroxymonosulfate (PMS) system to eliminate tetracycline (TC). The obtained Fe-Co@SPC could efficiently activate PMS and degrade 95.6 % of TC within 1 h at pH 9.06. Notably, the presence of HCO₃⁻ promoted PMS activation, which was mainly because the weakly alkaline system inhibited metal ion leaching. PO₄³⁻ invaded the surface active sites on the Fe-Co@SPC and formed O-P/C-PO₃, which inhibited PMS activation. The scavenging and EPR analysis results demonstrated SO₄^•−, •OH, ¹O₂ and O₂^•− were the major ROS. Besides, the C=O functional group and Fe-Co bimetal on Fe-Co@SPC accelerated the electronic transfer. Three reaction pathways were proposed in the Fe-Co@SPC/PMS system and the potential ecotoxicity of the intermediates was significantly declined. Based on the reusability and stability, Fe-Co@SPC could efficiently activate PMS to degrade organic pollutants in water bodies.