Amino-functionalized Fe3O4@SiO2 core-shell magnetic nanomaterial as a novel adsorbent for aqueous heavy metals removal

A novel amino-functionalized Fe3O4@SiO2 magnetic nanomaterial with a core-shell structure was developed, aiming to remove heavy metal ions from aqueous media. The structural, surface, and magnetic characteristics of the nanosized adsorbent were investigated by elemental analysis, FTIR, N-2 adsorption-desorption, transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, vibrating sample magnetometry, thermogravimetric analysis, and zeta-potential measurement. The amino-functionalized Fe3O4@SiO2 nanoadsorbent exhibited high adsorption affinity for aqueous Cu(II), Pb(II), and Cd(II) ions, resulting from complexation of the metal ions by surface amino groups. Moreover, the adsorption affinity for heavy metal ions was not much impacted by the presence of a cosolute of humic acid (10.6 mg/L) or alkali/earth metal ions (Na+, K+, Mg2+) (0.025-0.30 mmol/L). The metal-loaded Fe3O4@SiO2-NH2 nanoparticles could be recovered readily from aqueous solution by magnetic separation and regenerated easily by acid treatment. Findings of the present work highlight the potential for using amino-functionalized Fe3O4@SiO2 magnetic nanoparticles as an effective and recyclable adsorbent for the removal of heavy metal ions in water and wastewater treatment. (C) 2010 Elsevier Inc. All rights reserved.