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Yamazaki, Akio*; Okubo, Takahiro*; Iwadate, Yasuhiko*; Tachi, Yukio
no journal, ,
A structural analysis of water-filled pores in saturated compacted Ca-type montmorillonite was conducted by 1H NMR spectroscopy. The pore structure including interlayer and intraparticle pores in Ca-type compacted montmorillonite was characterized by relaxation time observed by 1H NMR and their correlations with water-filled pore sizes.
Okubo, Takahiro*; Tachi, Yukio
no journal, ,
The structures of Cs adsorption on montmorillonite were investigated by the nuclear magnetic resonance (NMR) spectroscopy. NMR parameters were evaluated by the first principle calculations in order to identify the relationship between adsorbed Cs structures and NMR parameters.
Nakajima, Katsuki*; Okubo, Takahiro*; Tachi, Yukio
no journal, ,
The structures of Cs adsorption on montmorillonite were investigated by the nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra of Cs adsorbed on montmorillonite samples were measured under different Cs contents and relative humidity levels and were analyzed to evaluate the change in the structure of hydrated Cs sorbed on montmorillonite.
Shimoyama, Iwao; Honda, Mitsunori; Kogure, Toshihiro*; Baba, Yuji; Yaita, Tsuyoshi; Okamoto, Yoshihiro
no journal, ,
We examined decontamination of radioactively contaminated soil in Fukushima using cesium free mineralization (CFM). Radioactivity concentration was measured by an NaI detector before and after heat treatments in atmosphere and under low-pressure condition with CaCl
or KCl additives. Without additives, decontamination ratios were about 5 and 20% for heat treatments in atmosphere and low-pressure conditions, respectively. With CaCl additive, similar decontamination ratios were observed for atmosphere and low-pressure heating, and it reached to 97% at 790
C. X-ray diffraction analysis showed that clay minerals in the soil disappeared after the heating and products depended on the pressure condition during heating. With KCl additive, higher decontamination ratio was observed for heating under low pressure than in atmosphere, and it reached to 83% at 790C. Because clay minerals remained after the heating with KCl, we consider that most Cs was removed through ion exchange. These results clarified that CFM is effective for actual soil in Fukushima and that Cs removal process depends on the reagent as additives.