Construction of Bi2O3/CuNiFe LDHs composite and its enhanced photocatalytic degradation of lomefloxacin with persulfate under simulated sunlight.

• Bi 2 O 3 /CuNiFe LDHs was employed to activate persulfate (PS) under simulated sunlight. • A synergistic effect between photochemical and catalytic processes was achieved. • Several reaction pathways and the mechanism of LOM degradation were proposed. • Bi 2 O 3 /CuNiFe LDHs exhibited good reusability and high stability at natural pH. Advanced oxidation methods based on photocatalysis and sulfate radicals have attached most interest towards contaminant degradation. However, there are a lack of coupling two methods in the field of pollutant degradation. In the present study, a new Bi 2 O 3 /CuNiFe LDHs composite was fabricated and it could efficiently activate persulfate (PS) for lomefloxacin (LOM) decomposition under simulated sunlight, in which 84.6% of LOM (10 mg·L−1) was degraded over 40 min with 0.4 g·L−1 of Bi 2 O 3 /CuNiFe LDHs composite and 0.74 mM of PS at natural pH. In addition, the Bi 2 O 3 /CuNiFe LDHs composite possessed good reusability and stability at least four runs. Moreover, active radical scavenging experiments indicated that hydroxyl radicals (HO·), sulfate radicals (SO 4 ·−), superoxide radicals (O 2 ·−) and hole (h+) were the main radicals under LOM degradation process. Subsequently, the possible degradation intermediates were determined and the decomposition pathways were put forward. At the same time, activated sludge inhibition experiments were performed to assess the variation of toxicity of LOM and its degradation intermediates during oxidation. Finally, possible reaction mechanism of Bi 2 O 3 /CuNiFe LDHs composite for PS activation under simulated sunlight was proposed. [ABSTRACT FROM AUTHOR]