A novel microbial-mediated strategy for iron doping into manganese oxide and its application in peroxymonosulfate-activated advanced oxidation of ofloxacin

Microbial synthesis enabled the incorporation of Fe into α-Mn 2 O 3 . • Biogenic Fe-doped α-Mn 2 O 3 surpasses its chemogenic counterpart in PMS activation. • The degradation mechanism of ofloxacin was elucidated. • Degradation intermediates of ofloxacin were evaluated for biotoxicity. For the same material, adopting a microbially guided fabrication method rather than conventional chemical synthesis can intriguingly enhance its catalytic performance. In this study, cost-effective Fe-doped α-Mn 2 O 3 was microbially synthesized to achieve higher degradation efficiency of ofloxacin (OFL) in a peroxymonosulfate (PMS)-based advanced oxidation process. Structural characterization reveals that microbially mediated Fe doping into α-Mn 2 O 3 induced lattice contraction, increased the Mn(III) fraction, and retained the MnO 6 octahedral framework. Biogenic Fe-doped α-Mn 2 O 3 achieved nearly complete degradation (99.98%) of OFL within 20 min (0.46 min −1 ), with the reaction rate constant elevated 8.51-fold compared to its chemically synthesized counterpart. Meanwhile, electrochemical analyses demonstrate that it exhibited higher anodic current density, faster electron transfer kinetics, and smaller charge transfer resistance–features more favorable for PMS activation to generate reactive oxygen species, thereby enabling efficient OFL degradation, with the oxidative contribution following the order of 1 O 2  > SO 4 •−  >  • OH. Density functional theory calculations reveal that Fe incorporation into α-Mn 2 O 3 strengthened molecular adsorption and reduced the surface electron escape barrier. This work provides a biologically inspired paradigm to boost the catalytic performance of abundant, cost-effective transition metal oxides without reliance on complex fabrication approaches. Download: Download high-res image (206KB) Download: Download full-size image