Heterogeneous degradation of cefotaxime sodium with peroxymonosulfate activated by an effective and magnetically separable Ni0.5Zn0.5Fe2O4 catalyst

Abstract

Magnetic Ni0.5Zn0.5Fe2O4 was fabricated by a simple solvothermal method, characterized by a variety of technologies, and used to activate PMS for the degradation of cefotaxime sodium (CFX) in water. The results indicated that Ni0.5Zn0.5Fe2O4 showed superior catalytic activity than that of ZnFe2O4 and NiFe2O4. Factors affecting the degradation of CFX were investigated, including PMS concentration, catalyst dosage, initial pH, reaction temperature and water matrices. The quenching experiments and electron paramagnetic resonance (EPR) measurements verified the generation of SO4•-, •OH and 1O2 in the Ni0.5Zn0.5Fe2O4/PMS system. Plausible mechanism on the activation of PMS was proposed according to the XPS analysis of Ni0.5Zn0.5Fe2O4 before and after reaction, showing that Ni2+ and Zn2+ were responsible for the radical generation and Fe3+ was not reactive to the activation of PMS. Additionally, the reusability experiments proved the good stability of Ni0.5Zn0.5Fe2O4. When the Ni0.5Zn0.5Fe2O4/PMS process was used to treat real river water spiked with CFX, the removal of CFX was much faster than that in deionized water. Thence, the Ni0.5Zn0.5Fe2O4/PMS system might be a candidate for removing antibiotics in environmental remediation.