Novel BiOBr/MWCNTs nanomaterials with electron transfer channels for degradation of levofloxacin under simulated solar irradiation

Constructing photocatalytic systems with efficient electron transfer pathways is an important development direction to improve the catalytic performance. A layered BiOBr/MWCNTs composite photocatalyst was successfully synthesized via a glycol-assisted solvothermal method . The photocatalytic activity was estimated by the degradation of levofloxacin (LEV) under simulated solar light irradiation . A variety of characterization techniques were carried out to explore the structural properties, surface functional groups, and electrochemical characteristics of composites. The results demonstrated that BiOBr/MWCNTs-0.5 % exhibited superior performance in LEV degradation (94.11 %) within 6 h under the synergy with H 2 O 2 . Radical scavenging experiments confirmed that superoxide radicals (‧O 2 - ) and hydroxyl radical (‧OH) were the primary active species. The introduction of multi-walled carbon nanotubes MWCNTs effectively enhanced the separation efficiency of photogenerated charges, significantly suppressed electron-hole recombination, thereby extended the lifetime of electron carriers. Moreover, liquid chromatography mass spectrometry (LC-MS) analysis revealed four possible degradation pathways for LEV, including demethylation , decarboxylation , defluorination , and ring cleavage of the piperazine and quinolone moieties, and the ecological risk of intermediate products was evaluated by Ecological Structure-Activity Relationship Model (ECOSAR) program. More importantly, the stability, reusability of the BiOBr/MWCNTs catalyst and the excellent mineralization ability for LEV are more conducive to its practical application. This study provides new insights into the application of MWCNTs in semiconductor photocatalysts and offers valuable references for the efficient photocatalytic degradation of quinolone antibiotics . Illustrated summary: MWCNTs was used as photogenerated electron capture carriers to enhance photocatalytic activity. • As an electron acceptor, MWCNTs accelerate electron transfer and improve photocatalytic performance. • The doping of MWCNTs significantly improved the photocatalytic activity, reusability and stability. • In this system, ·O 2 - and ·OH played a crucial role as the key active species. • Revealed potential photodegradation pathways and ecological risks of intermediates.