Preparation and photocatalytic properties of NH₂—Fe₃O₄@polyethylene glycol@ZnO nanospheres

The amino functionalized Fe₃O₄(NH₂—Fe₃O₄) had been successfully prepared as magnetic core. With zinc nitrate hexahydrate (Zn(NO₃)₂·6H₂O) as zinc source and polyethylene glycol(PEG, PEG-400) as surfactant, the magnetic composite based on zinc oxide and PEG-400-modified (NH₂—Fe₃O₄@PEG@ZnO) composite was synthesized by hydrothermal process. The composition, morphology and magnetic properties of the NH₂—Fe₃O₄@PEG@ZnO composite were characterized by a series of techniques including XRD, SEM, TEM, XPS, UV-VIS-NIR spectroscopy, specific surface area analyzer(BET), vibrating sample magnetometer(VSM) and so on. The photocatalytic performance of NH₂—Fe₃O₄@PEG@ZnO composite under ultraviolet light was investigated by using the degradation of Rhodamine B (RhB) dye as a simulated pollutant. The influencing factors such as the atomic ratio of Fe to Zn(n(Fe)∶n(Zn)), reaction temperature, types and dosages of surfactant on photocatalytic degradation performance were investigated by one-factor method. The results show that NH₂—Fe₃O₄@ZnO composite has good photocatalytic activity which is synthesized by n(Fe)∶n(Zn) is 1∶15 and the hydrothermal temperature is 180℃. The degradation rate of 50 mL RhB(1.0×10⁻⁵ mol·L⁻¹) is 90.36% when use 0.0500 g NH₂—Fe₃O₄@ZnO composite as a catalyst under ultraviolet light within 20 min. The specific surface area of NH₂—Fe₃O₄@PEG@ZnO composite is 11.43 m²·g⁻¹, the forbidden band width is about 2.51 eV and degradation rate of RhB is up to 99.36%. After 10 times of recycling, the photocatalytic degradation rate of RhB can still reach 96.48%. The combination of NH₂−Fe₃O₄@ZnO composite and PEG-400 has a synergistic effect on improving the photocatalytic activity.