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

The 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. This research reveals the synergistic effect of photo‐Fenton and Z‐type heterojunction of MIL‐88B(Fe)/BiOBr in the degradation of CIP. Cyclic conversion of Fe(III)/Fe(II) and selective activation of H2O2 are achieved by the Z‐type heterojunction structure. MIL‐88B(Fe)/BiOBr shows superior photocatalytic‐Fenton‐like performance for CIP degradation at near‐neutral‐pH (5.7) and low H2O2 (0.5 mM) conditions, which is valuable for practical applications.