In this research, we illustrate the synthesis of nano-sized ?- and ?-Al 2 O 3 with the new precursor by modified sol–gel method. Triethanolamine (TEA), diethylene glycol (DEG) and ethylene glycol (EG) were employed as gelling agent. Citric acid (CA) and aluminium nitrate nonahydrate (Al(NO 3 ) 3 .9H 2 O), were used as chelating agent and Al 3+ source, respectively. The nanostructure products were characterized by TGA, DTA, FT-IR, XRD and FE-SEM. The XRD results revealed that the lowest temperature for preparation of the ?- and ?-Al 2 O 3 obtained at 800 °C and 1200°C respectively. The average crystallite size for ?- and ?-Al 2 O 3 samples were about 14.5 and 28 nm, respectively. The SEM images show different morphologies by changing the proportions of CA: TEA/EG/DEG molar ratios. For characterization of optical properties of alpha alumina nanoparticles, photoluminescence (PL) and ultraviolet–visible spectroscopy (UV-Vis) were considered. The PL emission spectra of ?-Al 2 O 3 assumed that the hydroxyls groups present in the Al 2 O 3 structure are the responsible for strong photoluminescence emission at 507 nm. Next, removal of heavy metal ions (lead and cadmium) by adsorption on ?-alumina investigated. Various experimental parameters; pH, adsorbent dosage, and contact time, were iected for their effects on the adsorption of Pb(II) and Cd(II) from water. The maximum lead and cadmium removal were obtained at: pH 5; 5 and 50 mg adsorbent dosage for Pb(II) and Cd(II) respectively, and contact time of 20 and 30 min for Pb(II) and Cd(II), respectively. The equilibrium study showed that the adsorption data of both metals followed the Freundlich isotherm model. It was determined that adsorption process on to ?-Al 2 O 3 established good potentiality to remove Pb(II) and Cd(II) from aqueous solutions.
