A binary and ternary adsorption study of wastewater Cd(II), Ni(II) and Co(II) by γ-Fe2O3 nanotubes

Development of adsorbents for mitigation of toxic ions is one of the most important areas of rapid waste-water treatment Iron oxide especially in nano form has adsorptive potential for removing cations due to their structural properties. This study evaluates the behavior of gamma-Fe2O3 nanotubes to adsorb Cd(II), Ni(II) and Co(II) in mono- and multi-component (binary and ternary) systems. Time dependent studies for single ion adsorption followed pseudo second-order kinetic model for all the three ions. The isotherm data were well fitted to Langmuir model compared to Freundlich model. The experimentally obtained maximum loading capacities were estimated as 94.33, 86.206, and 60.60 mg g(-1) of gamma-Fe2O3 nanotubes for Cd(II), Ni(II) and Co(II) respectively from single ion solutions. Isotherm have been used to obtain the thermodynamic parameters. The results from the studies of sequential adsorption-desorption cycles showed that gamma-Fe2O3 nanotubes adsorbent held good desorption and reusability. (C) 2013 Elsevier B.V. All rights reserved.