Adsorption of Pb(II) from an Aqueous Solution by Titanium Dioxide/Carbon Nanotube Nanocomposites: Kinetics, Thermodynamics, and Isotherms

In the present study, titanium dioxide/multiwalled carbon nanotubes (TiO 2 /MWCNTs) nanocomposites have been synthesized, characterized, and used for the adsorption of Pb(II) from aqueous solution. The pH effect, kinetics, adsorption isotherms, and thermodynamics are examined in batch experiments. The time dependence of Pb(II) adsorption onto TiO 2 /MWCNTs and MWCNTs nanocomposites can be described by a pseudosecond-order kinetic model. The Langmuir isotherm model agrees well with the equilibrium experimental data. The maximum adsorption capacity of TiO 2 /MWCNTs and MWCNTs nanocomposites has been found to be (137.0 and 33.0) mg·g −1, respectively. Various thermodynamic parameters such as the Gibbs energy (Δ G °), enthalpy (Δ H °), and entropy (Δ S °) changes are calculated. Our results have shown that TiO 2 /MWCNTs nanocomposites can be used as an effective adsorbent for Pb(II) due to the high adsorption capacity as well as the short adsorption time needed to achieve equilibrium.