Demnitz M, Molodtsov K, Schymura S, Schierz A, Müller K, Jankovsky F, Havlova V, Stumpf T, Schmidt M
Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Resource Ecology, Research Site Leipzig, Permoserstr. 15, 04318 Leipzig, Germany.
J Hazard Mater. 2022 Feb 5;423(Pt A):127006. doi: 10.1016/j.jhazmat.2021.127006. Epub 2021 Aug 21.
Crystalline rock is one of the host rocks considered for a future deep geological repository for highly active radiotoxic nuclear waste. The safety assessment requires reliable information on the retention behavior of minor actinides. In this work, we applied various spatially resolved techniques to investigate the sorption of Curium onto crystalline rock (granite, gneiss) thin sections from Eibenstock, Germany and Bukov, Czech Republic. We combined Raman-microscopy, calibrated autoradiography and µTRLFS (micro-focus time-resolved fluorescence spectroscopy) with vertical scanning interferometry to study in situ the impact of mineralogy and surface roughness on Cm(III) uptake and molecular speciation on the surface. Heterogeneous sorption of Cm(III) on the surface depends primarily on the mineralogy. However, for the same mineral class sorption uptake and strength of Cm(III) increases with growing surface roughness around surface holes or grain boundaries. When competitive sorption between multiple mineral phases occurs, surface roughness becomes the major retention parameter on low sorption uptake minerals. In high surface roughness areas primarily Cm(III) inner-sphere sorption complexation and surface incorporation are prominent and in selected sites formation of stable Cm(III) ternary complexes is observed. Our molecular findings confirm that predictive radionuclide modelling should implement surface roughness as a key parameter in simulations.
结晶岩是未来用于处置高活性放射性毒性核废料的深层地质处置库所考虑的主岩之一。安全评估需要有关次锕系元素保留行为的可靠信息。在这项工作中，我们应用了各种空间分辨技术来研究锔在来自德国艾本施托克和捷克布科夫的结晶岩（花岗岩、片麻岩）薄片上的吸附情况。我们将拉曼显微镜、校准放射自显影和μTRLFS（微聚焦时间分辨荧光光谱）与垂直扫描干涉测量相结合，以原位研究矿物学和表面粗糙度对表面上锔（III）吸收和分子形态的影响。锔（III）在表面上的非均相吸附主要取决于矿物学。然而，对于同一矿物类别，锔（III）的吸附量和吸附强度会随着表面孔洞或晶界周围表面粗糙度的增加而增加。当多个矿物相之间发生竞争性吸附时，表面粗糙度成为低吸附量矿物上的主要保留参数。在高表面粗糙度区域，主要是锔（III）内球吸附络合和表面掺入较为突出，并且在选定位置观察到稳定的锔（III）三元络合物的形成。我们的分子研究结果证实，预测性放射性核素建模应将表面粗糙度作为模拟中的关键参数。
