The removal of Hg(II) ions from aqueous solutions by using thiol-functionalized cobalt ferrite magnetic nanoparticles

Mercaptopropyl-coated cobalt ferrite (CoFe 2 O 4 ) magnetic nanoparticles synthesized using the co-precipitation method and surface modified using the Stöber method were investigated as a convenient and effective adsorbent for aqueous Hg 2+ ions. The surfaces of the colloidal-CoFe 2 O 4 nanoparticles were functionalized with tetraethoxysilane and 3-mercaptopropyltrimethoxysilane via the co-condensation process. The characteristics of these particles were assessed at different stages of the production process using X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, and vibrating-sample magnetometry. The adsorption capacity of the mercaptopropyl-coated CoFe 2 O 4 nanoparticles with respect to the aqueous Hg 2+ ions was evaluated using atomic absorption spectrometer. It was found that the pH value of the model solution, the mass of the adsorbent, the temperature and the time of the adsorption significantly influence the sorption of Hg 2+ ions on the mercaptopropyl-coated cobalt ferrite nanoparticles. The maximum removal efficiency of the aqueous Hg 2+ ions was 97 % at room temperature and neutral pH value.