Magnetic Co-based carbon materials derived from core-shell metal-organic frameworks for organic contaminant...

The exploitation of highly efficient and reusable catalysts based on peroxymonosulfate (PMS) activation has attracted considerable attention in the environmental catalysis field. Herein, Co-doped graphitic carbon (Co-GC) on nitrogen-doped carbon (NC@Co-GC) was constructed and first employed as an efficient heterogeneous catalyst to activate PMS for the removal of organic contaminants. Coupled with only 0.5 mM PMS, NC@Co-GC could achieve 96.7% removal of reactive brilliant red within 14 min. Most importantly, the rate constant of NC@Co-GC was 7 times higher than that of commercial Co₃O₄. Additionally, NC@Co-GC with PMS could also exhibit high elimination rates of other dyes and organic contaminants including 8-hydroxy-quinoline, ciprofloxacin and phenol for the same condition. Benefiting from the magnetic properties, the catalyst could be separated and recycled by a magnet. Through the combination of the electron paramagnetic resonance (EPR) technology and the radical quenching experiments, it could be concluded that four types of ROS including ¹O₂, SO₄˙^-, ˙OH and O₂˙^- were involved and ¹O₂ played a dominant role in 3BF elimination. Interestingly, the catalytic efficiency remarkably improved and the rate constant increased by 3-fold in the presence of Cl^-, which always played a negative role and functioned as a ROS scavenger in a previous study. This report will inspire new studies for the development of a Co-based catalyst with both high efficiency and extraordinary reusability.