Catalytic activation of peroxymonosulfate by intrinsic defects in amorphous carbon: Enhanced electronic transfer and oxygen-functional groups

Inherent defects in carbon material serve as an important way to enhance peroxymonosulfate (PMS) activity, however, the mechanism that activates PMS has always been ambiguous. Herein, the pyrolysis of straw with Prussian blue nanoparticles to prepare CoFe2O4/C (Carbon) was applied to analyze the mechanism of defective amorphous-C catalyzed activation of PMS. Amorphous-C structural defects increased the specific surface area of CoFe2O4/C (from 44.19 to 108.73 m2/g) with triggered electronic rearrangement, resulting in more PMS adsorption. CoFe2O4/C ensured the supply of low-valent metals (≡Co2+ and ≡Fe2+) simultaneously introduced a large number of surface oxygen-containing functional groups, which facilitated free radical generation. The structural defects enhanced electron transfer contributing to the direct oxidative degradation of BPA. Thus, 100 % removal of 450 µM BPA was achieved within 40 min attributed to the combined effect of catalyst-mediated ∙OH, 1O2, and electron transfer. Furthermore, the CoFe2O4/C/PMS system for BPA degradation exhibited universal pH suitability (4 ∼ 10) and low metal leaching (452.10 and 19.53 μg/L for Co and Fe, respectively). This study constructs systematic support for proposing the catalytic mechanism of carbon intrinsic defects activated PMS.