Thermodynamic and kinetic investigations of uranium adsorption on amberlite IR-118H resin.

The adsorption behavior of uranium(VI) on a strongly acidic cation exchanger amberlite IR-118H has been studied as a function of the solution concentration and temperature. Results have been analyzed by Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption 7.14kJmol(-1) was calculated from the D-R adsorption isotherm. In order to understand the significance of the diffusion mechanisms and to accurately estimate the diffusivities inside the adsorbent particles, a model for uranium(VI) adsorption on amberlite IR-118H was used. The rate constants have been calculated for 293, 313 and 333K using Lagergren equation and the activation energy (E(a)) was derived using the Arhenius equation. The thermodynamic quantities for the process of adsorption have been estimated by plotting Ln K(D) versus 1/T. The DeltaH(o) and DeltaG(o) values of uranium(VI) adsorption on amberlite IR-118H show endothermic heat of adsorption; higher temperatures favor the process.