MgO–MgFe2O4 composites with magnetism and adsorption capacity for Congo red were synthesized by an ion exchange route using magnesium carbonate as templates. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and magnetic hysteresis loop were carried out to characterize the crystalline phase, microstructure, and magnetic property of as-obtained MgO–MgFe2O4 composites. Congo red adsorption experiments were conducted to evaluate the adsorption property of the as-synthesized samples. The results showed that the as-synthesized MgO–MgFe2O4 composites have a hierarchical structure, magnetic properties and good adsorption performance. The optimized sample exhibited an excellent adsorption capacity (498 mg g−1) for Congo red, which is much higher than many other hierarchical magnetic materials.
