Distribution of uranium on zeolite X and investigation of thermodynamic parameters for this system

The sorption of U(VI) from aqueous solutions on zeolite X has been studied by a batch technique. Distribution coefficients (K_d) were determined for sorption systems as a function of sorbate concentration, pH, contact time and temperature. The sorption isotherm was formed according to the Langmuir isotherm. Thermodynamic parameters have been determined at different temperatures. The ΔH° values for U(VI) on zeolite X were -29.5147 kJ mol^-1 at 313 K at pH 3 and -19.8705 kJ mol^-1 at 303 K at pH 9. The sorption of U(VI) on zeolite X is an exothermic in nature. Negative values of ΔG° show the spontaneous values for U(VI) that become less negative at higher temperatures, which shows that sorption is less favoured at higher temperatures.