Adsorption characteristics of 47 elements on a calcareous soil, a red earth and an alumina: a multitracer study.

The distribution coefficients, Kd of 47 elements from Na to Bi on a calcareous soil, a red earth and an alumina were, respectively, determined using a multitracer technique. The multitracer solution was prepared by irradiation of UO2(NO3)2 with 40Ar ion beam. It was found that there is a common general trend of variation in Kd for both soils and the alumina, i.e. all the shapes of plots of log Kd versus electron binding energy (Iz) are an 'inverted V', hence the important role of chemical interaction in the adsorption of trace inorganic cations, anions and neutral complexes on the soils and the oxides was demonstrated. For the alkali and alkaline earth elements, the common sequences of Kd values on the three adsorbents were Na+ < K+ < Rb+ < Cs+ (except for Rb+ on the alumina) and Mg2+ < Sr2+ < Ba2+ and accord with the sequences of effective ionic radii or single ion hydration enthalpies.