Kinetic Study and Sorption Mechanism of Uranium (VI) onto NaY Zeolite

Radioactive Uranium (VI) was removed by adsorption on NaY zeolite. The synthesized NaY zeolite sorbent was characterized with several techniques: X-ray diffraction XRD, scanning electronic microscopy MEB and Infrared spectroscopy measurements FTIR. Textural properties were detennined by N-2 adsorption isotherm. Batch adsorption experiments were performed to study the adsorption of uranium (VI) from aqueous solutions on NaY zeolite material. Operating variables studied include solution pH, contact time and temperature. Equilibrium data were analyzed by the Langmuir, Freundlich and Dubinin-Radushkevich models. The equilibrium data were best represented by the Langmuir isothenn model. Sorption kinetic data were fitted using pseudo first order, pseudo second order models and Intraparticule diffusion model. The experimental data fitted very well the pseudo second order model. The process mechanism was found to be complex, consisting of both mass transfer and intraparticle diffusion. The thermodynamic parameters such as standard free energy Delta G(0), standard enthalpy Delta H-0 and standard entropy Delta S-0 have been determined which indicates a spontaneous exothermic adsorption process.