Synthesis of CoFe2O4@SiO2–NH2 and its application in adsorption of trace lead

Abstract

In this work, an amine functionalized CoFe₂O₄ magnetic nanocomposite material CoFe₂O₄@SiO₂–NH₂ was prepared successfully by modifying coated-CoFe₂O₄@SiO₂ magnetic nanoparticles with 3-aminopropyltriethoxysilane (APTES) and became an efficient adsorbent for the separation and analysis of trace lead in water. The CoFe₂O₄@SiO₂–NH₂ magnetic nanoparticles were characterized using SEM, TEM, XRD, FTIR, VSM and BET techniques. Then, the adsorption mechanism was preliminarily investigated through ZETA, XPS, and adsorption kinetic experiments. The adsorption process was fitted by pseudo-second-order kinetics and a Langmuir isotherm model. The main adsorption mechanism of CoFe₂O₄@SiO₂–NH₂ towards lead ions was the chelation between the amino groups of CoFe₂O₄@SiO₂–NH₂ and lead cations, as well as the strong Coulomb interaction between the electron donor atoms O and N in the surface of CoFe₂O₄@SiO₂–NH₂ and lead cations. The adsorption capacity is 74.5 mg g⁻¹ and the adsorbent can be reused 5 times. Hence, this prepared CoFe₂O₄@SiO₂–NH₂ could find potential applications for the removal of trace metal ions in surface water.