Magnetic silica nanoparticles for the removal of Pb+2 from water

Abstract

Zero valent iron impregnated silica nanoparticles (Fe⁰/n-SiO₂) were synthesized using sol-gel process followed by supercritical drying, wet impregnation and hydrogen reduction. The synthesized nanoparticles were characterized by nitrogen Brunauer–Emmett–Teller (N₂-BET), Scanning Electron Microscopy, Transmission Electron Microscopy, Scanning Electron Microscopy with Energy-Dispersive X-ray spectroscopy, Vibrating Sample Magnetometer and X-ray diffraction techniques. Prepared samples were found to be magnetic with ultra-low density (0.048 g/mL) and high surface area (422 m²/g). Prepared samples were evaluated for adsorptive removal of Pb⁺² (5, 10, 25 and 50 ppm) from contaminated water. Results indicated that the adsorption of Pb⁺² was faster at lower concentrations (5 and 10 ppm) as > 80 % of Pb⁺² was removed within 480 minutes. At higher concentrations, the adsorption was slower, and the removal efficiency of 51.24 and 21.78 % were observed for 25 and 50 ppm Pb⁺² respectively, whereas for bare SiO₂ nanoparticles, it was 39.64 and 14.04 %.