Removal of Pb(II) and As(V) using magnetic nanoparticles coated montmorillonite via one-pot solvothermal reaction as adsorbent

Abstract

Clay mineral (montmorillonite) based nanocomposites was modified their surface functional groups for removal of Pb(II) and As(V) of aqueous solution. Magnetic nanoparticles with an amine functionalized surface (MH) were successfully synthesized onto the surface layer of montmorillonite (Mt) as an organomodified mineral solid via one-pot solvothermal reaction. The synthesis of amino magnetic nanoparticles coated montmorillonite (Mt@MH) was carried out by one-pot solvothermal reaction of 1,6-hexanediamine, iron(III) chloride hexahydrate and Mt in ethylene glycol at ±198 °C for 6 h. The MH nanoparticles with diameter size around 30–50 nm were obtained. Characterizations were performed using powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), superconducting quantum interference device (SQUID), and Fourier transform infrared spectroscopy (FT-IR) analysis. The insertion of MH onto the surface layer of Mt does not only serve as an easily retrievable adsorbent but also provide a high adsorption capacity towards Pb(II) and As(V) ion. The adsorption isotherms of Pb(II) and As(V) at room temperature were well-fitted with Langmuir model providing maximum adsorption capacity for Pb(II) and As(V) of 38.15 mg/g at pHe˜6.5 and 19.10 mg/g at pHe˜3.5, respectively. The Mt@MH showed 2-fold higher adsorption capacity than MH and Mt. It is due to surface functionalization with the amine group (6 mmol/g) on the adsorbent. The electrostatic interaction was proposed as the primary driving forces for Pb(II) and As(V) adsorption onto the Mt@MH.