Australian Nuclear Science and Technology Organisation, Menai, Australia.
J Environ Radioact. 2011 Oct;102(10):888-95. doi: 10.1016/j.jenvrad.2010.04.005. Epub 2010 May 8.
Adsorption of radionuclides on soils and sediments is commonly quantified by distribution coefficients (K(d) values). This paper examines the relationship between K(d) values for uranium(VI) adsorption and the specific surface area (SSA) of geologic materials. We then investigate the potential applicability of normalising uranium (U) K(d) measurements using the SSA, to produce 'K(a) values' as a generic expression of the affinity of U for the surface. The data for U provide a reasonably coherent set of K(a) values on various solid phases, both with and without ligands. The K(a) representation provides a way of harmonising datasets obtained for materials having different specific surface areas, and accounting for the effects of ligands in different systems. In addition, this representation may assist in developing U sorption models for complex materials. However, a significant limitation of the K(a) concept is that sorption of radionuclides at trace levels can be dominated by interactions with specific surface sites, whose abundances are not reflected by the SSA. Therefore, calculated K(a) values should be interpreted cautiously.
土壤和沉积物中放射性核素的吸附通常通过分配系数（K(d) 值）来定量。本文研究了铀(VI)吸附的 K(d) 值与地质材料比表面积（SSA）之间的关系。然后，我们研究了使用 SSA 归一化铀（U）K(d)测量值以产生“K(a) 值”作为 U 对表面亲和力的通用表示的潜在适用性。对于各种固相，无论是否存在配体，U 的 K(a) 值数据都提供了一组相当一致的 K(a) 值。K(a)表示形式提供了一种协调具有不同比表面积的材料的数据的方法，并考虑了不同系统中配体的影响。此外，这种表示形式可能有助于为复杂材料开发 U 吸附模型。然而，K(a)概念的一个显著限制是，痕量水平下放射性核素的吸附可能主要受到与特定表面位点相互作用的控制，而 SSA 并不能反映这些表面位点的丰度。因此，计算得出的 K(a) 值应谨慎解释。
