Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstrasse 400, 01328 Dresden, Germany.
Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Research Site Leipzig, 04318 Leipzig, Germany.
Environ Sci Technol. 2021 Apr 20;55(8):4871-4879. doi: 10.1021/acs.est.0c07998. Epub 2021 Mar 11.
The interaction of Eu(III) with thin sections of migmatized gneiss from the Bukov Underground Research Facility (URF), Czech Republic, was characterized by microfocus time-resolved laser-induced luminescence spectroscopy (μTRLFS) with a spatial resolution of ∼20 μm, well below typical grain sizes of the material. By this approach, sorption processes can be characterized on the molecular level while maintaining the relationship of the speciation with mineralogy and topography. The sample mineralogy was characterized by powder X-ray diffraction and Raman microscopy, and the sorption was independently quantified by autoradiography using Eu. Representative μTRLFS studies over large areas of multiple mm reveal that sorption on the heterogeneous material is not dominated by any of the typical major constituent minerals (quartz, feldspar, and mica). Instead, minor phases such as chlorite and prehnite control the Eu(III) distribution, despite their low contribution to the overall composition of the material, as well as common but less studied phases like Mg-hornblende. In particular, prehnite shows high a sorption uptake as well as strong binding of Eu to the mineral surface. Sorption on prehnite and hornblende happens at the expense of feldspar, which showed the highest sorption uptake in a previous spatially resolved study on granitic rock. Similarly, sorption on quartz is reduced, even though only low quantities of strongly bound Eu(III) were found here previously. Our results illustrate how competition of mineral surfaces for adsorbing cations drives the metal distribution in heterogeneous systems.
Eu(III)与来自捷克布科夫地下研究设施（URF）混合岩薄片的相互作用通过微焦点时间分辨激光诱导发光光谱（μTRLFS）进行了表征，其空间分辨率约为 20 μm，远低于材料的典型晶粒尺寸。通过这种方法，可以在保持形态与矿物学和形貌关系的同时，在分子水平上表征吸附过程。通过粉末 X 射线衍射和拉曼显微镜对样品矿物学进行了表征，并通过使用 Eu 的放射性自显影术独立定量了吸附作用。对多个毫米大面积的代表性 μTRLFS 研究表明，在不均匀的材料上的吸附作用不受任何典型主要组成矿物（石英、长石和云母）的控制。相反，尽管它们对材料的总体组成的贡献较低，但次要相（如绿泥石和绿帘石）以及常见但研究较少的相（如 Mg-角闪石）控制着 Eu(III)的分布。特别是，绿帘石具有高的吸附摄取量以及Eu 与矿物表面的强结合。绿帘石和角闪石上的吸附作用以长石为代价发生，长石在前一次对花岗岩的空间分辨研究中显示出最高的吸附摄取量。同样，尽管先前在此处发现的强结合 Eu(III)数量较少，但石英上的吸附作用也减少了。我们的结果说明了矿物表面竞争吸附阳离子如何驱动不均匀系统中金属的分布。
