Amino acid-assisted synthesis of superparamagnetic CoFe2O4 nanostructures for the selective adsorption of organic dyes

Abstract

We report a facile synthesis of superparamagnetic CoFe₂O₄ nanostructures with the assistance of an amino acid (lysine). Monodisperse CoFe₂O₄ nanospheres and nanoparticles were obtained by adjusting the synthesis parameters (such as the molar ratio of reactants and the solvent). The samples were characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, and Fourier-transform infrared spectroscopy. The magnetic property and measured zeta potential shows that both CoFe₂O₄ nanostructures were superparamagnetic and positively charged. The adsorption performance of the CoFe₂O₄ nanostructures was evaluated using different dyes, namely, methylene blue, Congo red, Acid Blue 80, methyl orange, rhodamine B, and Cationic red X-GTL, as models. The results show that CoFe₂O₄ nanospheres consisting of nanoparticles display high adsorption performance on methylene blue, methyl orange, and Congo red, whereas CoFe₂O₄ nanoparticles prefer adsorbing rhodamine B and Congo red. Therefore, the tunable synthesis of superparamagnetic CoFe₂O₄ nanostructures provides promising applications for the selective and highly efficient removal of various organic contaminants from industrial effluents.