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杉浦 佑樹; 戸村 努*; 石寺 孝充; 土井 玲祐; Francisco, P. C. M.; 塩飽 秀啓; 小林 徹; 松村 大樹; 高橋 嘉夫*; 舘 幸男
Journal of Radioanalytical and Nuclear Chemistry, 324(2), p.615 - 622, 2020/05
被引用回数：4 パーセンタイル：45.45(Chemistry, Analytical)Batch sorption experiments were performed to investigate the sorption mechanism of Se on montmorillonite under reducing conditions in deep geological environments. Based on Eh-pH diagrams and ultraviolet-visible spectra, Se was dissolved as selenide (Se(-II)) anions under the experimental conditions. The distribution coefficients (
; m
kg
) of Se(-II) indicated ionic strength independence and slight pH dependence. The values of Se(-II) were higher than those of Se(IV), which also exists as an anionic species. X-ray absorption near edge spectroscopy showed that the oxidation state of Se-sorbed on montmorillonite was zero even though selenide remained in the solution. These results suggest that Se(-II) was oxidized and precipitated on the montmorillonite surface. Therefore, it is implied that a redox reaction on the montmorillonite surface contributed to high values for Se(-II).
杉浦 佑樹; 戸村 努*; 土井 玲祐; 石寺 孝充; 舘 幸男
no journal, ,
We carried out batch sorption and XAFS experiments in various solution conditions identifying the aqueous species to evaluate the sorption behavior of Se(-II) onto montmorillonite. The 
values were independent of ionic strength. The values were nearly constant between pH 8-11, while the value decreased around pH 12. The aqueous species of Se(-II) were stable in 7d, and hydroselenide (HSe
) was the dominant species at pH 8; whereas, polyselenide (Se
, Se
) increased with the increase of pH. These behavior implies that Se(-II) sorption onto the edge site of montmorillonite by complexation is not a dominant sorption mechanism. The XANES spectra indicate that Se in the collected solid phase exists as Se(0). These results suggest that the values were independence of ionic strength and pH due to the oxidation and precipitation of Se by contacting montmorillonite in this work.
