One-step hydrothermal synthesis of carbon@Fe₃O₄ nanoparticles with high adsorption capacity

The magnetic carbon@Fe₃O₄ nanoparticles have been fabricated by a simple one-step hydrothermal method and applied as adsorbents for removal of organic dyes such as Congo red from aqueous solution. The prepared products were characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectra, thermo-gravimetric analysis, nitrogen adsorption-desorption isotherms, UV-vis spectrum, and vibrating sample magnetometer. The adsorption performances of the products were tested with removal of Congo red from aqueous solution. The carbon@Fe₃O ₄ nanoparticles possess high adsorption capacity and excellent magnetic separability by an external magnetic field, which is attributed to its high specific surface area providing more surface active sites.