Adsorption study of Heavy Metals from Aqueous Solutions using Magnetite Nanoparticles

Abstract

Contamination of heavy metals in wastewater is a significant worldwide problem, which is causing to detrimental effect on human health and environment. In present work, magnetite nanoparticles were used for the expulsion of Pb(II) and Cd(II) ions from aqueous solutions at varying pH conditions, contact time and adsorbent amounts. Magnetite nanoparticles were synthesized by co-precipitation method. Synthesized nanoparticles were characterized by XRD, FTIR, UV-Vis, VSM and SEM techniques for structural, optical, magnetic and morphological properties. The crystalline nature of magnetite nanoparticles with crystallite size 10.16 nm was confirmed by XRD. Optical properties and functional group identification of magnetite nanoparticles were revealed by UV-Vis and FTIR spectroscopy respectively. VSM measurements showed that the saturation magnetization of magnetite nanoparticles was 56.42 emu/g. This indicates that after adsorption, an easy separation of metal loaded magnetite nanoparticles from aqueous solutions can be achieved by applying the external magnetic field. Adsorption experiments results showed that the adsorption capacity of magnetite nanoparticles is higher for Pb(II) ions. At optimum conditions, the maximum removal efficiencies for Pb(II) and Cd(II) ions were 98.6% and 93% respectively. Langmuir and Freundlich adsorption isotherms were found suitable for adsorption processes. The adsorption kinetic data for both the metal ions were best fitted by pseudo second order reaction. Surface images of bare and metal loaded magnetite nanoparticles supported the confirmation of adsorption of metal ions on nanoparticles surface. Thus, it is concluded that magnetite nanoparticles can be effectively used as an adsorbent for expulsion of heavy metals from aqueous solutions.