Magnetic ordered mesoporous Fe ₃ O ₄ /CeO ₂ composites with synergy of adsorption and Fenton catalysis

Magnetic Fe ₃ O ₄ /CeO ₂ composites with highly ordered mesoporous structure and large surface area were synthesized by impregnation-calcination method, and the mesoporous CeO ₂ as support was synthesized via the hard template approach. The composition, morphology and physicochemical properties of the materials were characterized by XRD, SEM, TEM, XPS, Raman spectra and N ₂ adsorption/desorption analysis. The mesoporous Fe ₃ O ₄ /CeO ₂ composite played a dual-function role as both adsorbent and Fenton-like catalyst for removal of organic dye. The methylene blue (MB) removal efficiency of mesoporous Fe ₃ O ₄ /CeO ₂ was much higher than that of irregular porous Fe ₃ O ₄ /CeO ₂ . The superior adsorption ability of mesoporous materials was attributed to the abundant oxygen vacancies on the surface of CeO ₂ , high surface area and ordered mesoporous channels. The good oxidative degradation resulted from high Ce ³⁺ content and the synergistic effect between Fe and Ce. The mesoporous Fe ₃ O ₄ /CeO ₂ composite presented low metal leaching (iron 0.22 mg L ⁻¹ and cerium 0.63 mg L ⁻¹ ), which could be ascribed to the strong metal-support interactions for dispersion and stabilization of Fe species. In addition, the composite can be easily separated from reaction solution with an external magnetic field due to its magnetic property, which is important to its practical applications.