Selenite and selenate uptaken in ettringite: Immobilization mechanisms, coordination chemistry, and insights from structure
Selenite and selenate uptaken in ettringite: Immobilization mechanisms, coordination chemistry, and insights from structure
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DOI：
10.1016/j.cemconres.2017.07.004
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发表时间：
2017-10
影响因子：
11.4
通讯作者：
B. Guo;K. Sasaki;T. Hirajima
中科院分区：
文献类型：
--
作者：
B. Guo;K. Sasaki;T. Hirajima
虽然钙矾石是硒固定化的关键材料，但钙矾石中吸附的硒的固定化机制、原子构型和柱间结构尚不清楚。硒含氧阴离子的固定机制进行了评估，通过结构洞察钙矾石。对固定化后的固体残渣进行了SeO 32-和SeO 42-的化学性质对比。与结构SO 42 −的含氧阴离子交换是SeO 42 −固定化的主要机制。相比之下，SeO 32 −很容易固定在钙矾石中形成内球复合物。此外，揭示SeO 32 −络合位点对于理解SeO 32 −的固定化机理是必要的。基于键价理论的表征结果，提出了SeO 32-在钙矾石结构中的定位位置。在这项工作中获得的结果是相关的理解硒及其同位素固定在水泥或碱性环境中，特别是核废料管理。
Although ettringite is a crucial material in terms of Se immobilization, the immobilization mechanisms, atomic configuration, and intercolumn structure of Se sorbed in ettringite are unclear. The immobilization mechanism of Se oxoanions was evaluated through structural insight into ettringite. It is contrasting between SeO32 −and SeO42 −in chemical property of the solid residues after immobilization. The oxoanion exchange with structural SO42 −is the main mechanism for immobilization of SeO42 −. In contrast, SeO32 −is easily immobilized to form inner-sphere complexes in ettringite. In addition, it is necessary to reveal the SeO32 −complexation sites for understanding the mechanisms in immobilization of SeO32 −. Based on the characterization results with the bond valence theory, the location sites of sorbed SeO32 −in ettringite structure were proposed. The results obtained in this work are relevant to the understanding of Se and its isotopes immobilized in cement or alkaline environments, especially for nuclear waste management.