Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Saxony 01328, Germany.
Environ Sci Technol. 2021 Dec 7;55(23):15797-15809. doi: 10.1021/acs.est.1c04413. Epub 2021 Nov 23.
Reactive transport modeling (RTM) is an essential tool for the prediction of contaminants' behavior in the bio- and geosphere. However, RTM of sorption reactions is constrained by the reactive surface site assessment. The reactive site density variability of the crystal surface nanotopography provides an "energetic landscape", responsible for heterogeneous sorption efficiency, not covered in current RTM approaches. Here, we study the spatially heterogeneous sorption behavior of Eu(III), as an analogue to trivalent actinides, on a polycrystalline nanotopographic calcite surface and quantify the sorption efficiency as a function of surface nanoroughness. Based on experimental data from micro-focus time-resolved laser-induced luminescence spectroscopy (μTRLFS), vertical scanning interferometry, and electron back-scattering diffraction (EBSD), we parameterize a surface complexation model (SCM) using surface nanotopography data. The validation of the quantitatively predicted spatial sorption heterogeneity suggests that retention reactions can be considerably influenced by nanotopographic surface features. Our study presents a way to implement heterogeneous surface reactivity into a SCM for enhanced prediction of radionuclide retention.
反应迁移模型（RTM）是预测生物和地质环境中污染物行为的重要工具。然而，吸附反应的 RTM 受到反应表面位点评估的限制。晶体表面纳米形貌的反应位点密度变化提供了一个“能量景观”，负责不均匀的吸附效率，这是当前 RTM 方法所没有涵盖的。在这里，我们研究了 Eu(III)（作为三价锕系元素的模拟物）在多晶纳米形貌方解石表面上的空间非均相吸附行为，并定量研究了表面纳米粗糙度对吸附效率的影响。基于微焦点时分辨激光诱导发光光谱（μTRLFS）、垂直扫描干涉测量和电子背散射衍射（EBSD）的实验数据，我们使用表面纳米形貌数据对方程模型进行参数化。定量预测的空间吸附非均质性的验证表明，保留反应可能会受到纳米形貌表面特征的显著影响。我们的研究提出了一种将非均相表面反应纳入 SCM 以增强放射性核素保留预测的方法。
