A novel persulfate activation strategy by double Z-scheme Bi2O3/CuBi2O4/BiOBr heterojunction: Non-radical dominated pathway for levofloxacin degradation

Persulfate advanced oxidation technology (PS-AOPs) is known as a novel wastewater treatment method. Considering the poor self-stability of Bi₂O₃/CuBi₂O₄, we synthesized Bi₂O₃/CuBi₂O₄/BiOBr ternary composite material and established the non-radical pathway-dominated peroxymonosulfate (PMS) activation system. The study indicated that BiOBr promoted electron migration on the material surface. Bi₂O₃/CuBi₂O₄/BiOBr/Vis/PMS system exhibited excellent catalytic performance (86.83 % within 100 min), significantly higher than Bi₂O₃/CuBi₂O₄ (63.19 %) and BiOBr (60.35 %). Furthermore, it has strong catalytic activity and adaptability to various environmental conditions. By quenching experiments and EPR analysis, ${\text{O}}_2^{-}\bullet$ and 1O₂ were the main active species. Finally, possible degradation pathways and intermediates were predicted through liquid mass spectrometer (LC-MS), and toxicity analysis was conducted on levofloxacin (Lev) and intermediates. The degradation mechanism may be attributed to the construction of double Z-scheme heterojunction, photogenerated electron transfer and ROS generation through the redox cycle of Cu²⁺/Cu⁺ and Bi⁵⁺/Bi³⁺.