Kinetic Study on Pb(II) Adsorption from Aqueous Solutions on Carbon Materials

Abstract

The adsorption of lead ions (Pb (II)) ions from aqueous solutions was studied. Different types of carbon materials, such as high-porous carbon, BAU-A activated carbon, multi-walled carbon nanotubes (pristine and oxidized), were used as adsorbents. To describe kinetic dependences for the Pb (II) extraction from aqueous solutions with those materials, the following models were implemented: pseudo-first-and pseudo-second-order, intraparticle diffusion, and Elovich. The adequacy of applying the pseudo-second-order equation was presented for characterizing the Pb (II) adsorption on the carbon materials under study. Thus, it was found that the interaction between the adsorbed ions and the functional groups of the adsorbents makes an important contribution to the overall rate of the process. Finally, the time of achieving equilibrium, the adsorption rate constants and the maximum adsorption capacity were empirically determined for all the adsorbents.