Magnetic 0D/1D ZnFe2O4/ZnCO3 Rod-Shaped Nanocomposites and Its in Situ Conversion to ZnFe2O4/ZnO with Boosting and Stable Photo-Fenton Activity for Organic Pollutants

Photo-Fenton catalysis plays an important role in the degradation of organic pollutants in environmental sewage. In this paper, magnetic 0D/1D ZnFe2O4/ZnCO3 rod-like nanocomposites were fabricated by a simple one-pot solvothermal method, and then the produced magnetic 0D/1D ZnFe2O4/ZnO rod-like nanocomposites were formed via calcination at high temperature. The obtained 0D/1D ZnFe2O4/ZnCO3 has been fully investigated by x-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and vibrating sample magnetometry. Furthermore, the photocatalytic Fenton reaction of these two catalysts has been preliminarily evaluated for the degradation performance of organic dyes and antibiotics in wastewater. The results showed that, under visible-light irradiation, the ZnFe2O4/ZnCO3 composite material and its product, ZnFe2O4/ZnO, after high-temperature firing can achieve more than 90% photo-Fenton catalytic degradation of Rhodamine B (RhB) and tetracycline (TC) within 30 min, superior to that of ZnFe2O4, ZnCO3 , and ZnO monomers due to their larger specific surface area and more active sites. The magnetization saturation values of ZnFe2O4/ZnCO3-2 and ZnFe2O4/ZnO-2 were, respectively, around 34.20 emu/g and 15.00 emu/g, indicating that both have good magnetic recovery properties. After five cycles of experiments, the photo-Fenton catalytic properties of ZnFe2O4/ZnCO3-2 and ZnFe2O4/ZnO-2 on TC decreased slightly within 30 min, but the Fenton catalytic properties of RhB still maintained more than 98%, indicating that both have good magnetic recovery properties and strong structural stability. A possible photo-Fenton catalytic mechanism has been proposed based on free radical identification, electrochemical impedance spectra, photocurrent curves, and a Mott-Schottky diagram. This study provided two catalysts with excellent performance for the photo-Fenton catalytic degradation of pollutants in water.