Ultrafast degradation of emerging organic pollutants via activation of peroxymonosulfate over Fe3C/Fe@N-C-x: Singlet oxygen evolution and electron-transfer mechanisms

Fe3C/Fe decorated N-doped magnetic carbon materials (denoted as Fe3C/Fe@N-C-x) were successfully fabricated via facile one-pot calcination of MIL-88B(Fe) with a green precursor of melamine. Benefiting from the co-existence of sp2-hybridized C–π moieties, oxygen-containing groups (CO and O–CO), N-doping species and ferreous nanoparticles (FNPs), the as-obtained Fe3C/Fe@N-C-9 exhibited excellent activation of peroxymonosulfate (PMS) for ultrafast elimination of various emerging organic contaminants with high mineralization capacities. Inspired by the unique nanotube morphology and encapsulation of FNPs, the Fe3C/Fe@N-C-9 possessed trace Fe leaching and can be magnetically separated for an easy recycling. Combining with competitive radical scavenging tests, electron spin resonance (ESR), electrochemical analysis and in-situ Raman spectra, the singlet oxygen (1O2) and electron-transfer can be accounted for the organic pollutant removal. Because of that, the Fe3C/Fe@N-C-9 exhibited good resistance to inorganic anions and natural organic matters (NOMs). It was fascinating that Fe3C/Fe@N-C-9 achieved satisfactory treatment efficiency for real pharmaceutical wastewater. [Display omitted] •Fe3C/Fe decorated N-doped magnetic carbon materials were fabricated via pyrolysis.•The removal rate of SMX over Fe3C/Fe@N-C-9 +PMS system was fastest (2.84 min−1).•The system possessed excellent mineralization and anti-interference capacities.•1O2 evolution and electron-transfer pathway were the underlying catalysis mechanisms.•The Fe3C/Fe@N-C-9 +PMS system can effectively treat real pharmaceutical wastewater.