Preparation of γ-Al2O3 nanoparticles using modified sol-gel method and its use for the adsorption of lead and cadmium ions

In this research, nano-sized γ-Al2O3 particles were synthesized by modified sol-gel method using new precursors. In this study, aluminium nitrate, ethylene glycol (EG), citric acid (CA) and triethanolamine (TEA) were used as an Al3+ source, gel, chelating and surfactant agents, respectively. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA) and infrared spectroscopy (IR). Then, the removal efficiency of heavy metal ions (lead and cadmium) in the adsorption process by the as-synthesized alumina nanoparticle has been investigated and the effect of various experimental parameters such as pH, adsorbent dosage and exposure time were examined. The maximum removal was obtained at pH 5.0 by the as-synthesized adsorbent at the contact time of the 20 min and 30 min for Pb(II) and Cd(II) respectively. The equilibrium study showed that the adsorption data of both metal ions followed the Freundlich isotherm model. Then, regeneration study on the synthesized adsorbent was performed and it was found that the adsorbent can be successfully regenerated up to 3 times with the high level of adsorption.