Core-shell magnetic Fe3O4@Zn/Co-ZIFs to activate peroxymonosulfate for highly efficient degradation of carbamazepine

A core-shell metal-organic framework encapsulated Fe3O4 magnetic particles (Fe3O4@Zn/Co-ZIFs) was designed and synthesized successfully to activate peroxymonosulfate (PMS) for carbamazepine (CBZ) degradation. It exhibits superior catalytic performance since the unique interior structure and synergistic effect between ZIFs shell and Fe3O4 core, achieving 100% removal of CBZ (5 mg/L) within 30 min. The outer wrapping structure of ZIF-8 can stabilize the ZIF-67 and Fe3O4 under intricate reaction conditions to restrain the leaching of Co ions (as low as 0.067 mg/L). Further investigation found that both SO4 center dot- and OH center dot contribute to the degradation of CBZ at initial stage, and SO4 center dot- gradually plays a pivotal role with the reaction time prolonging. The acceleration of electron transfer between Fe3O4 and cobalt active sites of Zn/Co-ZIFs could induce the redox cycling of Co2+ and Co3+. The possible degradation pathway was proposed by analyzing intermediates. This work extends the development of MOFs materials for environmental remediation.