Fe@C activated peroxymonosulfate system for effectively degrading emerging contaminants: Analysis of the formation and activation mechanism of Fe coordinately unsaturated metal sites

Authors：Chi, Haiyuan; Wan, Jinquan; Zhou, Xiaoxia^*; Sun, Jian; Yan, Bing

Source：Journal of Hazardous Materials, 2021, 419: 126535.

DOI：10.1016/j.jhazmat.2021.126535

• Carbon-encapsulated Fe
• Metal-organic framework
• Advanced oxidation technology
• Peroxymonosulfate
• Emerging contaminants

Carbon-encapsulated Fe nanocomposites (Fe@C), obtained by pyrolysis of metal-organic frameworks (MOFs), can activate peroxymonosulfate (PMS) to remove emerging contaminants (ECs). Unfortunately, the current MOFs-derived catalysts always inevitably produce more iron-oxide compounds that unfavorable for PMS activation. In this work, according to the thermogravimetric curve of Fe(II)-MOF-74, to discuss the role of pyrolysis temperature on the structural characteristics of Fe@C. The results demonstrated that Fe@C-4 could obtain abundant coordinately unsaturated metal sites and exhibited the best activation performance. Radical-quenching experiments and EPR measurements confirm that the generated sulfate radical (SO4-center dot) and singlet oxygen (O-1(2)) only degraded approximately 35% of TBBPA. Meanwhile, negatively charged complex intermediates formed by the weak interaction between Fe@C-4 and PMS was proposed as the dominant reactive species, and approximately 65% of TBBPA was degraded. This work optimizes the synthesis strategy and mechanism of Fe@C and provides a methodological reference for the design of Fe-based catalysts.

• Institution
  guangzhou university