Facile Hydrothermal Synthesis of Magnetic Sepiolite Clay for Removal of Pb(II) from Aqueous Solutions

Abstract

The sepiolite-iron oxide nanocomposite (Sepiolite-Fe3O4) was synthesized via facile hydrothermal method and used as an efficient magnetic adsorbent for removal of Pb(II) ions from water samples. The Sepiolite-Fe3O4 nanocomposite was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), vibration sample magnetometer (VSM) and scanning electron microscopy (SEM) techniques. The equilibrium data were tested using different isotherm models including Langmuir, Freundlich and Temkin. The adsorption isotherm fits well with the Langmuir model and the maximum Pb(II)-sorption capacity of 96.15 mg g-1 was calculated at room temperature. Kinetic data well interpreted with the pseudo-second-order model (R2 > 0.9998), that illustrated the adsorption process was controlled by chemical reactions. The as-prepared magnetic adsorbent was easily reused through sequential adsorption-desorption cycles, presenting that the Sepiolite-Fe3O4 nanocomposite has an acceptable stability and reusability. As a result, this study indicates that the novel adsorbent nanocomposite may be an ideal adsorbent for heavy metal-contaminated water treatment.