Hierarchical porous graphite-like carbon nanosheet cooperated with Fe/Fe3C@Fe-N-C nanocomposites toward catalytic oxidation process

In this work, Fe, N co-doped hierarchical porous graphite-like carbon with carbon-encapsulated Fe/Fe3C@ Fe -N-C was synthesized by a facile solid-phase synthesis strategy, and was employed as an efficient catalyst to activate peroxymonosulfate (PMS) for oxidation of tetracycline (TC). The optimal Fe-N/C 800 outlined a highly catalytic performance in activating peroxymonosulfate (PMS) with TC decomposition rate reaching 89.2 % in 20 min at ultra-low catalyst dosage. Meanwhile, the effect of operating parameters was also investigated in order to evaluate the potential of using Fe-N/C 800 in practical applications. In addition, the characterization analysis and experiments results elucidated that graphitic N, pyridinic N, C--O, Fe3C, Fe0 and FeN4 were considered as the main reactive species promoting the PMS activation to generate reactive oxygen species (ROS) (including singlet oxygen (1O2), sulfate radical (SO4 & BULL;-) and hydroxyl radical (& BULL;OH)). The electron paramagnetic resonance (EPR) experiments and radicals quenching analyses further demonstrated that the non-radical species singlet oxygen (1O2) was the dominant reactive oxygen species. Moreover, the TC degradation pathways were presented by LC-MS. Ultimately, the toxicity of the intermediate products were also investigated by ECOSAR system.