Preparation of multifunctional nanocomposites Fe3O4@SiO2–EDTA and its adsorption of heavy metal ions in water solution

Novel magnetic Fe 3 O 4 @SiO 2 -ethylenediamine tetraacetic acid (adsorbent) CMS–COOH-modified magnetic materials, CMS was prepared by surface modification of amino-functionalized Fe 3 O 4 @SiO 2 (-NH 2 -modified magnetic materials, NMS) with EDTA using water-soluble carbodiimide as the cross-linker in deionized water solution. The phase structure, infrared spectra, thermal analysis and magnetic properties of were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and vibrating sample magnetometry and its properties for removal of heavy metal ions under varied experimental conditions were also investigated. The results revealed that CMS had good tolerance to low pH and exhibited good removal efficiency for the metal ions. The maximum adsorption capacities of CMS were found to be 0.11 mmol g −1 for Cu(II) at pH5.0 (30 °C) and 0.14 mmol g −1 for Pb(II) ions at pH2.0 (30 °C).