LAUSR

The ability of Tunisian smectite, collected from Aleg Formation (Jebel Romena), in the adsorption of nickel (Ni(II) and chromium (Cr(III)) cations from aqueous solutions has been studied through a bath adsorption mechanism with respect to different optimal parameters including the amount of adsorption, pH, and contact time. The characterization of a smectite sample was performed using XRD, XRF, FT-IR, SEM, BET-specific surface area techniques, thermo-gravimetric analyses, and CEC. The process of adsorption kinetics was examined using the pseudo-first-order, the pseudo-second-order, and the intraparticle diffusion models. The results revealed that the adsorption of Ni(II) and Cr(III) cations was according to the pseudo-second-order model. The changes of the thermodynamic parameters such us the Gibbs free energy (ΔG), the enthalpy (ΔH), and entropy (ΔS) attested, spontaneous and endothermic between 10 and 40 °C.