▎ 摘　　要

BACKGROUND: In this study, a novel magnetic material was applied as an adsorbent for simultaneous removal of Pb(II) and Cd(II) ions from aqueous solutions. The adsorbent was synthesized using functionalized MnFe2O4 magnetic nanoparticles grafted to lamellar graphene oxide surface (MnFe2O4@SiO2-NH2@GO) and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis and magnetic measurements. RESULTS: The adsorbent exhibited superior adsorption properties for Pb(II) and Cd(II). The maximum uptake capacity of Pb(II) and Cd(II) reached 42.48 and 18.28 mg g(-1) within 30 min at 25 degrees C, respectively. The data for adsorption fitted well with the Langmuir isotherm and pseudo-second-order kinetic models, which indicated that the adsorption was via monolayer chemisorption on homogeneous sites. The calculation of thermodynamic parameters revealed spontaneous and endothermic adsorption processes accompanied by randomness increase. X-ray photoelectron spectroscopy analysis indicated that the coordination between nitrogen atoms of amino groups and the two types of heavy metal ions was a possible adsorption mechanism. CONCLUSIONS: MnFe2O4@SiO2-NH2@GO possesses the properties of high adsorption efficiency, fast separation, high stability and easy regeneration for adsorption of Pb(II) and Cd(II) ions. Thus, the as-prepared adsorbent is considered as a promising material for the removal of heavy metal ions and this research could offer a new means for water cleanup. (c) 2020 Society of Chemical Industry