3D structure of LaFe1-δCoδO3@carbon cloth composite catalyst for promoting peroxymonosulfate activation: Identification of catalytic mechanism towards multiple antibiotics

Abstract

In this work, LaFe_1-δCo_δO₃@carbon cloth (LFCO@CC) composite was synthesized via a hydrothermal method by partially substituting with Co in B-site of LaFeO₃ and assembling in-situ on carbon cloth (CC), which was successfully employed for peroxymonosulfate (PMS) activation to eliminate antibiotics in water. B-site partial substitution could form a bimetallic synergistic system, which was favorable to the Fe²⁺/Fe³⁺ and Co²⁺/Co³⁺ cycling and ROS production. Moreover, loading with the 3D structure of CC facilitated the provision of more active sites for LFCO with high density and good dispersion to improve the electron transport process and the catalytic activity. The catalytic performance of LFCO@CC towards four types of antibiotics (isoquinoline alkaloids, nitrofurans, tetracyclines and quinolones) were different, with the degradation efficiencies of 92.8 % (Berberine hydrochloride), 98.1 % (Ornidazole), 97.7 % (Tetracycline) and 85.1 % (Levofloxacin), respectively. The corresponding contributions of active species were also different; non-radical pathway played a dominant role in BH and TC degradation, whereas the degradation of OMZ and LVF was performed by a combination of non-radical and radical mechanism. Among them, ¹O₂ and e⁻ favored the degradation of BH, whereas the combination of SO₄⁻, O₂⁻, ¹O₂ and e⁻ favored the degradation of OMZ. Furthermore, the degradation pathway and toxicity of BH were proposed and LFCO@CC also demonstrated excellent anionic salt resistance and reusability. This work facilitated a deeper understanding of the diverse degradation mechanisms of various antibiotics by novel perovskite-based catalysts.