Facile fabrication of Fe/Fe3C embedded in N-doped carbon nanofiber for efficient degradation of tetracycline via peroxymonosulfate activation: Role of superoxide radical and singlet oxygen

The toxic metal ions leaching and metal nanoparticles agglomeration were the critical issues for metal based carbon materials during the peroxymonosulfate (PMS) activation processes. Herein, a facile strategy was first proposed that zero-dimensional Fe/Fe3C nanoparticles were embedded in one-dimensional N-doped carbon nanofiber (Fe/Fe3C@NCNF) to solve the above challenges. The as-obtained Fe/Fe3C@NCNF-800 possessed a low Ea value (11.7 kJ/mol) and exhibited high activity for activating PMS to degrade tetracycline (TC) in a wide range of pH 3-11. As expected, the iron ions leaching concentration of Fe/Fe3C@NCNF-800 was very low (0.082 mg/L). Meanwhile, the Fe/Fe3C@NCNF-800 was easily recovered from the reaction solution due to its magnetic properties. Both superoxide radicals (O-2(center dot)) and non radical of singlet oxygen (O-1(2)) were the primary reactive oxygen species (ROS) in the Fe/Fe3C@NCNF-800/PMS system via quenching tests and electron spin resonance spectroscopy (ESR). The catalytic mechanism suggested that the Fe/Fe3C and graphitic N were the main active sites in the Fe/Fe3C@NCNF-800 for PMS activation. This work provided a facile method for the preparation of Fe-based carbon materials with high catalytic ability, low metal leaching and easy recycling, showing a broad prospect for environmental applications. (C) 2021 Elsevier Inc. All rights reserved.