Oxidative degradation of the antibiotic oxytetracycline by Cu@Fe3O4 core-shell nanoparticles

A core-shell nanostructure composed of zero-valent Cu (core) and Fe3O4 (shell) ([email protected]3O4) was prepared by a simple reduction method and was evaluated for the degradation of oxytetracycline (OTC), an antibiotic. The Cu core and the Fe3O4 shell were verified by X-ray diffractometry (XRD) and transmission electron microscopy. The optimal molar ratio of [Cu]/[Fe] (1/1) in [email protected]3O4 created an outstanding synergic effect, leading to >99% OTC degradation as well as H2O2 decomposition within 10 min at the reaction conditions of 1 g/L [email protected]3O4, 20 mg/L OTC, 20 mM H2O2, and pH 3.0 (and even at pH 9.0). The OTC degradation rate by [email protected]3O4 was higher than obtained using single nanoparticle of Cu or Fe3O4. The results of the study using radical scavengers showed that OH is the major reactive oxygen species contributing to the OTC degradation. Finally, good stability, reusability, and magnetic separation were obtained with approximately 97% OTC degradation and no notable change in XRD patterns after the [email protected]3O4 catalyst was reused five times. These results demonstrate that [email protected]3O4 is a novel prospective candidate for the pharmaceutical and personal care products degradation in the aqueous phase.