Recyclable magnetic NiFeO/C yolk-shell nanospheres with excellent visible-light-Fenton degradation performance of tetracycline hydrochloride.

A photo-Fenton-like reaction was considered as an effective method for wastewater treatment because it could produce more oxidative species such as hydroxyl radicals (˙OH) to accelerate the reaction. In this paper, a NiFe2O4/C (abbr. as NFO/C) yolk-shell nanostructure was synthesized via one-step calcination using polyacrylic acid sodium salt (PAAS) NPs as a template. The nanocomposite was characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption, among others. The magnetically separable nanocomposite exhibited a high activity and recyclability towards the photodegradation of tetracycline hydrochloride (TC). In addition, the factors affecting the photodegradation process were systematically investigated, including the dosage of the NiFe2O4/C catalyst, the pH of the solution, and the volume of H2O2. Notably, the degradation rate of tetracycline hydrochloride (TC) reached 97.25% in 60 min in the presence of H2O2 under visible light irradiation (λ > 400 nm) with NiFe2O4/C. This work provides a simple and novel method to construct NiFe2O4/C yolk-shell nanostructures, which may be applied to the photodegradation of tetracycline hydrochloride from wastewater. Finally, a photocatalytic and stability mechanism is proposed, which may help us more comprehensively understand the photo-Fenton mechanism.