Synthesis, characterization and application of mesoporous silica/maghemite nanocomposite in removal of heavy metal ions from aqueous solution

In the present study, mesoporous silica/iron oxide nanocomposite (MCM-41/γ-Fe2O3) was prepared with hydrothermal method and then the application of the nanocomposite as an adsorbent for the removal of Ni(II), Cd(II), Cr(III), Pb(II) and Zn(II) ions from aqueous solution was investigated. Furthermore, the effects of the solution pH, contact time and adsorbent dosages on removal percentage were studied. The results indicated that the adsorption of these ions on the surface of the adsorbent increase with increasing of solution pH, contact time and adsorbent dosage. The maximum percent removal (in the condition of: pH=5, t=50min, w=0.16g) of Ni(II), Zn(II), Cd(II), Cr(III) and Pb(II) ions was reached 53, 79, 61, 89 and 99.5%, respectively. The synthesized mesoporous silica/iron oxide nanocomposite was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), nitrogen adsorption-desorption (BET) and Field Emission Scanning electron microscopy (FE-SEM). The concentrations of metal ions of the solutions were measured by atomic absorption spectroscopy (AAS). According to the results, MCM-41/γ-Fe2O3 nanocomposite exhibited a large surface area 461.19m2/g, a total pore volume 0.4128cm3/g, a mean pore diameter 3.58nm, a narrow pore size distribution and the superparamagnetic behavior.