The MOF/LDH derived heterostructured Co3O4/MnCo2O4 composite for enhanced degradation of levofloxacin by peroxymonosulfate activation

Abstract

In this study, metal–organic framework interfacing layered double hydroxide (MOF/LDH) derived heterostructured Co3O4/MnCo2O4 composite was synthesized and employed to activate peroxymonosulfate (PMS) for levofloxacin (LEV) degradation. With a greater pseudo-first-order reaction rate constant than those previously reported, approximately 96.9% of LEV (10 mg/L) could be decomposed within 30 min by the Co3O4/MnCo2O4/PMS catalytic system, which exhibited superior performance over single Co3O4 and MnCo2O4 catalyst. The influences of critical reaction parameters on LEV removal were evaluated and the experimental results indicated that Co3O4/MnCo2O4 possessed broad adaptability to solution pH, as well as appreciable practicality, universality and stability. By exposing more active sites through higher specific surface area and enhancing the electron transfer rate with heterostructure, the Co3O4/MnCo2O4 catalyst remarkably promoted the generation of reactive oxygen species (ROS) including SO4−, OH, O2− and 1O2, which were further verified by scavenger tests and electron paramagnetic resonance (EPR) technique. The transformation routes of LEV were elucidated according to the identified degradation intermediates. Finally, the underlying reaction mechanism was revealed on the basis of the results of characterizations and experiments. This work not only provided a novel strategy to improve the catalytic ability of conventional active components for PMS activation, but also brought new insights into the huge potential of mixed transition metal oxides, which would motivate future development of catalysts fabrication with advantageous microstructures and favorable properties for water pollution remediation.