MIL101 derived bimetallic oxide modified biochar for highly efficient activation of peroxymonosulfate toward ofloxacin degradation: Mechanism, degradation pathway, and toxicity analysis

Abstract

In this study, MIL101 (FeCo-MOF)-derived CoFe 2 O 4 was loaded onto biochar to form CoFe 2 O 4 /biochar (CFO@BC) composite using a solvothermal method followed by calcination under a nitrogen atmosphere. Morphological analysis revealed that CFO exhibited a rhombohedral spindle-shaped crystal structure with smaller grain size than pure FeCo-MOF-derived CoFe 2 O 4 and was uniformly dispersed on BC surface. Consequently, CFO@BC exhibited extraordinarily high activity to PMS, 92.6% of ofloxacin (OFL) was degraded in 40 min with a rate constant of 0.283 min −1 , which is approximately 2.25 times that measured for the CFO/PMS system. The radical quenching tests and EPR analysis demonstrated that 1 O 2 , SO 4 •- , •OH and O 2 •- were all involved in the degradation of OFL, with 1 O 2 and •OH serving as the predominant reactive species in the reaction system. Furthermore, this catalyst presented stable pH adaptability, strong resistance to interference across diverse and complex aqueous environments. Finally, the pathways, mechanism, toxicity of intermediate products for OFL degradation in this system was explored. This work offers both theoretical understanding and practical guidance for the structural regulation and performance enhancement of MOF-derived metal oxide/biochar composites as PMS-activated catalysts in the treatment of antibiotic-containing wastewater.