Adsorption of Organic Dyes by Fe3O4@C, Fe3O4@C@C, and Fe3O4@SiO2 Magnetic Nanoparticles

Fe3O4@C, Fe3O4@C@C, and Fe3O4@SiO2 core–shell nanoparticles are synthesized via thermal decomposition and coprecipitation. Samples are characterized via X-ray spectroscopy, transmission electron microscopy, and magnetometry. It is shown that the magnetic core of all nanoparticles is nanocrystalline and has crystal parameters corresponding to only one phase of Fe3O4, covered with a uniform shell of amorphous carbon or silicon oxide around 8 nm thick. Special attention is given to adsorption properties of the nanoparticles with respect to four dyes: Methylene blue, Congo Red, Eosin Y, and Rhodamine C. The high selectivity of Fe3O4@C nanoparticles to various dyes is revealed.