Gum kondagogu modified magnetic nano-adsorbent: An efficient protocol for removal of various toxic metal ions

Gum kondagogu (GK) modified magnetic iron oxide nanoparticles (MNP) have been prepared by co-precipitating Fe2+ and Fe3+ ions using ammonia solution in presence of GK biomacromolecules. The TEM analysis revealed the presence of nearly spherical size iron oxide particles with diameters in the range of 8-15 nm; while the XRD results confirmed the crystallinity of iron oxide nanoparticles. The magnetic measurements demonstrated the ferromagnetic behavior of GK-MNP with a magnetic saturation value of -60 emu/g. The removal efficiencies for a variety of metal cations by the GK-MNP were determined quantitatively in the order: Cd2+ > Cu2+ > Pb2+ > Ni2+ > Zn2+ > Hg2+ at a pH of 5.0 +/- 0.1 and at a temperature of 30.0 +/- 1.0 degrees C. A maximum of 106.8 mg/g and a minimum of 35.07 mg/g adsorption capacities were observed for the Cd2+ and Hg2+ ions, respectively using the Langmuir isotherm model. (C) 2011 Elsevier B.V. All rights reserved.