The Z‐Scheme MIL‐88B(Fe)/BiOBr Heterojunction Promotes Fe(III)/Fe(II) Cycling and Photocatalytic‐Fenton‐Like Synergistically Enhances the Degradation of Ciprofloxacin

Abstract

AbstractThe Z‐scheme MIL‐88B/BiOBr (referred to as MxBy, whereas x and y are the mass of MIL‐88B(Fe) and BiOBr) heterojunction photocatalysts are successfully prepared by a facile ball milling method. By adding low concentration H2O2 under visible light irradiation, the Z‐scheme heterojunction and photocatalytic‐Fenton‐like reaction synergistically enhance the degradation and mineralization of ciprofloxacin (CIP). Among them, M50B150 showed efficient photodegradation efficiency and excellent cycling stability, with 94.6% removal of CIP (10 mg L−1) by M50B150 (0.2 g L−1) under 90 min of visible light. In the MxBy heterojunctions, the rapid transfer of photo‐generated electrons not only directly decomposed H2O2 to generate ·OH, but also improved the cycle of Fe3+/Fe2+ pairs, which facilitated the reaction with H2O2 to generate ·OH and ·O2− radicals. In addition, the effects of photocatalyst dosages, pH of CIP solution, and coexisting substances on CIP removal are systematically investigated. It is found that the photocatalytic‐ Fenton‐like reaction can be carried out at a pH close to neutral conditions. Finally, the charge transfer mechanism of the Z‐scheme is verified by electron spin resonance (ESR) signals. The ecotoxicity of CIP degradation products is estimated by the T.E.S.T tool, indicating that the constructed photocatalysis‐Fenton‐like system is a green wastewater treatment technology.