Synthesis of CoFeO@SiO-NH and its application in adsorption of trace lead.

In this work, an amine functionalized CoFeO magnetic nanocomposite material CoFeO@SiO-NH was prepared successfully by modifying coated-CoFeO@SiO magnetic nanoparticles with 3-aminopropyltriethoxysilane (APTES) and became an efficient adsorbent for the separation and analysis of trace lead in water. The CoFeO@SiO-NH 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 CoFeO@SiO-NH towards lead ions was the chelation between the amino groups of CoFeO@SiO-NH and lead cations, as well as the strong Coulomb interaction between the electron donor atoms O and N in the surface of CoFeO@SiO-NH and lead cations. The adsorption capacity is 74.5 mg g and the adsorbent can be reused 5 times. Hence, this prepared CoFeO@SiO-NH could find potential applications for the removal of trace metal ions in surface water.