Pore structure-domoinated nonradical oxidation activity of self-dispersed Fe doped mesoporous-carbon for boosting antibiotics degradation efficiency

Abstract

Electron transfer process (ETP) mediated nonradical oxidation pathway exhibits high efficiency/selectivity for removing trace organic pollutants in complex water matrices. Pore structure regulation strategy is feasible for achieving nonradical pathways, but the detail influence of various pore structures was rarely elucidated. Here, three types of Fe doped mesoporous-carbon catalysts (Fe@MNC) with different pore structures were precisely synthesized, including ordered linear mesopores (Fe@o-LMC), disordered spherical mesopores (Fe@d-SMC) and disordered dendritic mesopores (Fe@d-DMC). There was a significant difference in sulfamethoxazole (SMX) degradation performance among three Fe@MNC/peroxymonosulfate (PMS) catalytic systems, with the pseudo first-order reaction rate constants (k_obs) followed by Fe@o-LMC (0.818 min⁻¹) > Fe@d-SMC (0.394 min⁻¹) > Fe@d-DMC (0.166 min⁻¹). Importantly, ETP pathway was responsible for SMX degradation, and the electron transfer intensity was the intrinsic reason for the difference in catalytic performance. Subsequently, the pore structure-dominated SMX degradation efficiency was elucidated by analyzing SMX mass-transfer inner the Fe@MNC: the more favorable the pore structure was for reactants mass transfer, the more favorable it was for triggering ETP, thereby leading higher degradation efficiency. Finally, the enhanced ETP of Fe@o-LMC/PMS system also exhibited excellent reactivity for the degradation of other electron-rich antibiotics, as well as adaptability under various water quality and excellent stability. This work reveals the pore structure effect in Fenton-like reaction, and provides a new insight into the design of ETP mediated nonradical based porous catalysts for efficient antibiotic removal from wastewater.