Pb(II) adsorption on magnetic γ-Fe2O3/titanate nanotubes composite

Magnetic γ-Fe2O3/titanate nanotubes (TNTs) composites were prepared and characterized by N2 adsorption/desorption, VSM, TEM, XRD and zeta potential analysis. The adsorption properties of γ-Fe2O3/TNTs towards Pb(II) were examined in this paper. Pb(II) could be adsorbed onto the surface of γ-Fe2O3/TNTs via electrostatic attraction and ion-exchange between Pb(II) and H+/Na+. The kinetics of the Pb(II) adsorption process on γ-Fe2O3/TNTs followed the pseudo-second-order kinetic model. The adsorption isotherm fitted Langmuir model well. Thermodynamic results indicated that the adsorption amounts of Pb(II) on γ-Fe2O3/TNTs increased with the elevation of temperature and the adsorption process was spontaneous and endothermic in nature. Pb(II) adsorption on γ-Fe2O3/TNTs was strongly dependent on pH and high pH favored the adsorption. The superparamagnetism of γ-Fe2O3/TNTs made the composites easily to be magnetic separated from the aqueous phase. The Pb(II)-adsorbed γ-Fe2O3/TNTs composites could be effectively desorbed and maintained excellent stability in the recycling process.