Construction of β-cyclodextrin modified Fe3O4 composites with enhanced peroxymonosulfate activation towards efficient degradation of norfloxacin

Abstract

In the current research study, β-cyclodextrin modified Fe3O4 (β-CD@Fe3O4) superparamagnetic composite materials were synthesized using co-precipitation and ultrasonication methods, with β-CD acting as a coating material. The as-prepared material was employed as a heterogeneous catalyst for the activation of peroxymonosulfate (PMS) for the removal of norfloxacin (NOR). The catalytic activities of bare Fe3O4, β-CD@Fe3O4 composites, and the β-CD@Fe3O4/PMS system were compared under various parameters. Results revealed that the β-CD@Fe3O4/PMS exhibited higher catalytic activities, and a removal efficiency of 99.12% with a rate constant of 0.1576 min−1 was achieved in 30 min under optimum conditions ([catalyst] = 0.4 g/L, [PMS] = 4.0 mM, [NOR] = 30 mg/L, pH = 7.0). In particular, the larger surface area of β-CD@Fe3O4 (120 m2g−1) and the presence of additional reactive sites accelerated the activation of PMS in comparison to bare Fe3O4 (70 m2g−1) and thereby promoted the mineralization of NOR. The impact of various pivotal factors on NOR abatement was also studied. Scavenging results and the EPR technique revealed that the SO4•−, •OH, and O2•−radicals participated in the removal of NOR in the β-CD@Fe3O4/PMS system. The Fe3+/Fe2+/Fe3+ redox cycle in β-CD@Fe3O4 is used for the activation of PMS and generates radicles. The reusability results show excellent stability of the catalyst material, and a loss of 4.35% was observed after four cycles. The results revealed that the β-CD@Fe3O4 composites can activate PMS and have potential for the degradation of various pollutants from the environment.