Metal-organic framework gel derived magnetic hierarchical porous Fe-N-C catalyst as peroxymonosulfate activator for efficient degradation of amoxicillin via singlet oxygen-dominated nonradical pathway

Abstract

The rational design of transition metal and nitrogen co-doped carbon-based catalysts for the efficient removal of antibiotics through non-radical pathway of peroxymonosulfate (PMS) activation has attracted widespread attention. Herein, a magnetic hierarchical porous Fe-N-C catalyst (FeBDC-NH2-800) was successfully constructed by pyrolyzing the hierarchical porous precursor metal–organic framework gel (FeBDC-NH2) consisting of nitrogen-containing ligands. Benefiting from the defective heterojunction structure, the catalyst exhibited effective and efficient degradation towards amoxicillin (AMX) by activating PMS to produce 1O2. The degradation of AMX was up to 97.4 % within 30 min, which was 2.48 and 2.16 times more than that of FeBDC-NH2/PMS and nanosized Fe3O4/PMS respectively. The high degradation performance could be maintained toward low pollutant concentration conditions and cycle experiments, manifesting its possibility for practical application. Combining the data of quenching experiments, electron spin resonance spectra, electrochemical experiments, X-ray photoelectron spectra and density functional theory calculation, the mechanism was revealed that radical pathway contributed little during degradation while singlet oxygen played a significant role. The cleavage of lattice oxygen and defective heterogeneous structure of FeBDC-NH2-800 contributed together to promote PMS for 1O2 production.