The synthesis of core-shell Fe₃O₄@mesoporous carbon in acidic medium and its efficient removal of dye

Magnetic core-shell Fe₃O₄@nSiO₂@mSiO ₂ nanoparticles were first synthesized with P123 as template in acid condition, which possess high BET surface area (839 m² g ^-1) and large pore volume (0.9 cm³ g^-1). Then Fe₃O₄@nSiO₂@mSiO₂ nanoparticles were used as hard templates to synthesize Fe₃O₄@mesoporous carbon (Fe₃O₄@mC) with large surface area (971 m ² g^-1) and pore volume (1.4 cm³ g ^-1). The high surface area and mesoporous structure of Fe ₃O₄@mC favor its efficient adsorption of Rhodamine B in aqueous solution, which exhibited higher adsorption capacity of 198.9 mg g ^-1 within 30 min than the previous reports on magnetic mesoporous graphitic carbon and magnetic mesoporous resin. The superparamagnetic property of Fe₃O₄@mC made it easily separated by an external magnetic field and reused after ethanol extraction. The rapid and efficient adsorption of dye together with their ease in separation and regeneration suggests that Fe₃O₄@mC composites have great potential applications in environmental abatements.