Ion exchange studies of europium on uranium antimonate

Abstract

Uranium antimonate (USb) has been prepared by the precipitation reaction between uranyl nitrate and potassium pyroantimonate and it has been characterized by X-ray diffraction (XRD), thermal analysis, energy disperse X-ray florescence, and pH titration. Ion exchange of europium on USb as a function of time, temperature, concentration of nitric acid and europium has been studied. The distribution coefficient of europium on USb was found to decrease from ∼10 5 ml g −1 at 0.05 M nitric acid to 22 ml g −1 at 2 M nitric acid. Uptake of europium was fitt to a particle diffusion equation and the diffusion coefficient ( D i) was calculated from the slope of Bt– t plots. The energy ( E a) and entropy (Δ S ∗) of activation for the sorption of europium were found to be 17 kJ mol −1 and −67.9 J mol −1 K −1, respectively. Sorption data obtained at various concentrations of europium were fitted into a Langmuir adsorption isotherm and the enthalpy change accompanied by the sorption of europium was determined by the temperature variation method.