Rapid removal and recovery of Pb(II) from wastewater by magnetic nanoadsorbents.

Iron oxide nanoadsorbents are cost-effective adsorbents that provide high adsorption capacity, rapid adsorption rate and simple separation and regeneration. In this study, Fe(3)O(4) nanoadsorbents have been employed for the removal of Pb(II) ions from aqueous solutions by a batch-adsorption technique. The effects of contact time, initial concentration of Pb(II) ions, temperature, solution pH and coexisting ions on the amount of Pb(II) adsorbed have been investigated. Pb(II) adsorption was fast, and equilibrium was achieved within 30 min. The amount of Pb(II) adsorbed increased as temperature increased, suggesting an endothermic adsorption. The optimal pH value for Pb(II) adsorption was around 5.5. Furthermore, the addition of coexisting cations such as Ca(2+), Ni(2+), Co(2+), and Cd(2+) has no remarkable influence on Pb(II) removal efficiency. The adsorption equilibrium data fitted very well to Langmuir and Freundlich adsorption isotherm models. The thermodynamics of Pb(II) adsorption onto the Fe(3)O(4) nanoadsorbents indicated that the adsorption was spontaneous, endothermic and physical in nature. The desorption and regeneration studies have proven that Fe(3)O(4) nanoadsorbents can be employed repeatedly without impacting its adsorption capacity.