Adsorption of γ-Picoline Onto Acid Activated Clay From Aqueous Solution.

The adsorptive interactions of γ-picoline molecule with acid activated clay in aqueous medium are investigated in this work. Batch adsorption studies were carried out with various γ-picoline concentrations, amount of clay adsorbents, pH, exchangeable cations, agitation time and temperature. The adsorption was strongly dependent on pH of the medium, and the uptake of γ-picoline increased from pH 1.0 to 6.0 and the uptake become constant from pH 7 to 10. Therefore all subsequent studies were carried out at pH 7. Pseudo-first-order, pseudo-second-order, the Elovich equation and intraparticle diffusion models were used to analyze the kinetic data obtained at different concentrations. Among the kinetic models studied, the pseudo-second-order was the best applicable model to describe the adsorption of γ-picoline onto activated clay. The equilibrium adsorption data were analyzed by Langmuir, Freundlich and Temkin isotherm models. The results indicated that the Freundlich model provides the best correlation of the experimental data.  The thermodynamic parameters, such as DH, DS and DG, were also determined and evaluated. Adsorption of γ-picoline onto acid activated bentonite was found to be an endothermic reaction with DH^◦ at 29 J/mol.