The uptake of selenite in calcite revealed by X-ray absorption spectroscopy and quantum chemical calculations
The uptake of selenite in calcite revealed by X-ray absorption spectroscopy and quantum chemical calculations
复制标题
X 射线吸收光谱和量子化学计算揭示了方解石中亚硒酸盐的吸收
DOI：
10.1016/j.scitotenv.2021.149221
复制
发表时间：
2022
影响因子：
9.8
通讯作者：
Takahashi Yoshio
中科院分区：
文献类型：
--
作者：
Yokoyama Yuka;Qin Hai-Bo;Tanaka Masato;Takahashi Yoshio
硒是环境中重要的微量元素，但硒与方解石之间的相互作用对硒的去向和地球化学行为的控制作用尚不完全清楚。在这项研究中，在方解石中的亚硒酸盐的吸收的分子尺度机制进行了研究，结合实验室实验，扩展X射线吸收精细结构（EXAFS）光谱，和量子化学计算。结果表明，亚硒酸盐可以很大程度上分布到方解石在circumneutral pH值。硒在方解石中的EXAFS分析，结合量子化学计算得到的本地结构，表明亚硒酸盐可以纳入方解石取代碳酸盐，和亚硒酸盐的几何不相容性可以容纳的晶体体积的轻微膨胀。这项研究的结果表明，方解石可能是一个潜在的硒汇，提供了一个重要的洞察了解硒的流动性和地球化学行为在地下环境中，特别是在地下水系统。
Selenium (Se) is an important trace element in the environment, but the interaction of Se with calcite that may control the fate and geochemical behavior of Se is not fully understood. In this study, the molecular-scale mechanism for the uptake of selenite in calcite was investigated by a combination of laboratory experiments, extended X-ray absorption fine structure (EXAFS) spectroscopy, and quantum chemical calculations. Results showed that selenite can be largely distributed to calcite at circumneutral pH. The local structure of Se in calcite obtained from EXAFS analyses, in combination with quantum chemical calculations, demonstrated that selenite can be incorporated into calcite by substituting for the carbonate, and that the geometric incompatibility of selenite could be accommodated by a slight expansion of crystal volume. The findings from this study suggest that calcite could be a potential Se sink, providing an important insight into the understanding of the mobility and geochemical behavior of Se in the subsurface environments particularly in the groundwater system.