Starch-functionalized magnetite nanoparticles for hexavalent chromium removal from aqueous solutions

Abstract

Superparamagnetic starch-functionalized magnetite nanoparticles (SMNPs), ranging from 6 to14 nm, were prepared by a co-precipitation synthesis protocol. The SMNPs were used as nanoadsorbents for the removal of Cr(VI) from aqueous medium by the batch adsorption technique. The SMNPs adsorption capacity was found to decrease with the increase in the pH of the Cr(VI) solution. Under optimum pH conditions, the maximum experimental adsorption capacity of SMNPs for Cr(VI) was found to be 26.6 mg g−1. While the adsorption was endothermic, the equilibrium adsorption data could be best fitted to the Freundlich adsorption isotherm model and its kinetics was in agreement with the pseudo-second-order rate equation. The SMNPs could be easily regenerated because of low adsorption activation energy. The SMNPs capacity for Cr(VI) removal remained almost undiminished even after its repeated use. © 2015 Balaban Desalination Publications. All rights reserved.