Synthesis of magnetic NiFe2O4/CuS activator for degradation of lomefloxacin via the activation of peroxymonosulfate under simulated sunlight illumination

Abstract

As a promising method, coupled advanced oxidation processes (AOPs) based on the photocatalytic and peroxymonosulfate (PMS) activation has attracted extensive attention to degrade organic pollutants. Therefore, heterogeneous photosensitive PMS activators with high activity and excellent stability played a crucial role in this process need to be developed. In this study, magnetic NiFe2O4/CuS composite powder was successfully synthesized based on a simple solvothermal method combined with co-precipitation method, which was applied in the catalytic degradation process of lomefloxacin (LOM). The mass ratio of ingredients was optimized, while the physical and chemical properties of as-prepared samples were analyzed though a series of characterizations. In addition, under the illumination of simulated sunlight, 88.1% of LOM could be eliminated over 40 min with the addition of 0.8 g L−1 PMS and 0.6 g L−1 NiFe2O4/CuS (1:5) at pH 5.86 (unadjusted). Radical scavenging experiments and EPR test analysis were carried out to prove the contribution of different active species in the degradation process. Besides, the possible degradation mechanism was proposed. The intermediate products produced during the degradation of LOM were detected by the high-performance liquid chromatography/mass spectrometry (HPLC/MS), and the possible degradation pathways were deduced. Finally, the recyclability of NiFe2O4/CuS and the stability of the new degradation system were elucidated.