Key Words:DEGRADATION

Abstract:Fe oxides are recognized as peroxymonosulfate (PMS) activators in degradation of pollutants, but their catalytic efficiency is limited. In this work, introduction of electron-rich species and hetero-metal was proposed to enhance PMS activation. Mn-doped and carbon encapsulated Fe7S8/Fe2O3/Fe (Mn-C@FeSO/Fe) catalysts were prepared via the low-temperature sulfuration of Mn-doped MIL-88A(Fe) under H2/Ar atmosphere. Mechanism studies indicated that trace Mn doping (0.007 wt%) facilitated the binding of PMS to the catalyst and generation of superoxide radical. The S and Fe0 species accelerated the redox cycling of Fe2+/Fe3+. Both of them resulted in a significant improvement of the catalytic activity, 96.0 % of ciprofloxacin (CIP) was degraded within 20 min in Mn-C@FeSO/Fe + PMS system with rate constant of 0.195 min-1, 9.2 times higher than that of C@Fe3O4/PMS. In a continuous degradation system, the removal ratio of CIP was above 80% in 24 h. Escherichia coli cultivation experiments and toxicity assessment software demonstrated that the bio-toxicity of the derived intermediates during CIP degradation was significantly reduced. This work integrates Mn, S, Fe0, and carbon species and elucidates their roles in improving PMS activation of Fe oxide, offering a new thought for resolving the sluggish reconversion of Fe2+.

Volume:505

Issue:

Translation or Not:no