Preparation of magnetic Ag/AgCl/CoFe2O4 composites with high photocatalytic and antibacterial ability

Abstract

Novel plasmonic photocatalysts, Ag/AgCl/CoFe₂O₄, were prepared via a two-step synthesis method. The obtained Ag/AgCl/CoFe₂O₄ composites were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible absorption spectroscopy (UV-vis). The magnetic properties of the samples were studied by vibrating sample magnetometer (VSM) analysis. Methyl orange (MO), bisphenol A (BPA) and ciprofloxacin (CIP) were used as target pollutants to investigate the degradation capability of Ag/AgCl/CoFe₂O₄. Results showed that the composite can degrade both colored and colorless pollutants, while Ag/AgCl/CoFe₂O₄ (3 : 1) composite showed the highest photoactivity in the degradation of MO. It can degrade about 93.38% MO in 1.5 h. The reactive species scavenger results indicated that hydroxyl radicals (˙OH) were not the main photooxidant, while holes (h⁺) and superoxide anion radicals (˙O₂⁻) played key roles in MO decoloration. Furthermore, the degraded solution of BPA was analyzed using high performance liquid chromatography (HPLC). The results showed that BPA was decomposed gradually. The composite was magnetically separated and investigated using three successive recycle experiments under visible light. The results exhibited that the photoactivity of Ag/AgCl/CoFe₂O₄ is stable. Besides, Ag/AgCl/CoFe₂O₄ also exhibited good antibacterial activity against Escherichia coli (E. coli). The method used to prepare the composite can be expanded and applied to synthesize other magnetically separable photocatalysts.