Adsorption of Pb(II) and Cd(II) from aqueous solutions using titanate nanotubes prepared via hydrothermal method.

Titanate nanotubes (TNs) with specific surface areas of 272.31 m(2)g(-1) and pore volumes of 1.264 cm(3)g(-1) were synthesized by alkaline hydrothermal method. The TNs were investigated as adsorbents for the removal of Pb(II) and Cd(II) from aqueous solutions. The FT-IR analysis indicated that Pb(II) and Cd(II) adsorption were mainly ascribed to the hydroxyl groups in the TNs. Batch experiments were conducted by varying contact time, pH and adsorbent dosage. It was shown that the initial uptake of each metal ion was very fast in the first 5 min, and adsorption equilibrium was reached after 180 min. The adsorption of Pb(II) and Cd(II) were found to be maximum at pH in the range of 5.0-6.0. The adsorption kinetics of both metal ions followed the pseudo-second-order model. Equilibrium data were best fitted with the Langmuir isotherm model, and the maximum adsorption capacities of Pb(II) and Cd(II) were determined to be 520.83 and 238.61 mg g(-1), respectively. Moreover, more than 80% of Pb(II) and 85% of Cd(II) adsorbed onto TNs can be desorbed with 0.1M HCl after 3h. Thus, TNs were considered to be effective and promising materials for the removal of both Pb(II) and Cd(II) from wastewater.