JOPSS - Search Results

Journal Articles

Selenide [Se(-II)] immobilization in anoxic, Fe(II)-rich environments; Coprecipitation and behavior during phase transformations

Francisco, P. C. M.; Matsumura, Daiju; Kikuchi, Ryosuke*; Ishidera, Takamitsu; Tachi, Yukio

Environmental Science & Technology, 56(5), p.3011 - 3020, 2022/03

https://doi.org/10.1021/acs.est.1c04216

Times Cited Count：2 Percentile：7.36(Engineering, Environmental)

Journal Articles

Certification of uranium isotope amount ratios in a suite of uranium ore concentrate certified reference materials

Zhang, R.*; Nadeau, K.*; Gautier, E. A.*; Babay, P. A.*; Ramella, J. L.*; Virgolici, M.*; Serban, A. E.*; Fugaru, V.*; Kimura, Yoshiki; Venchiarutti, C.*; et al.

Geostandards and Geoanalytical Research, 46(1), p.43 - 56, 2021/11

https://doi.org/10.1111/ggr.12409

Times Cited Count：10 Percentile：49.23(Geochemistry & Geophysics)

Journal Articles

Impacts of Si on Se(IV) immobilization on ferrihydrite; An in situ ATR-IR spectroscopic study

Francisco, P. C. M.; Tachi, Yukio

ACS Earth and Space Chemistry (Internet), 4(12), p.2366 - 2377, 2020/12

https://doi.org/10.1021/acsearthspacechem.0c00243

Times Cited Count：4 Percentile：17.18(Chemistry, Multidisciplinary)

Journal Articles

Sorption behavior of selenide on montmorillonite

Sugiura, Yuki; Tomura, Tsutomu*; Ishidera, Takamitsu; Doi, Reisuke; Francisco, P. C. M.; Shiwaku, Hideaki; Kobayashi, Toru; Matsumura, Daiju; Takahashi, Yoshio*; Tachi, Yukio

Journal of Radioanalytical and Nuclear Chemistry, 324(2), p.615 - 622, 2020/05

https://doi.org/10.1007/s10967-020-07092-x

Times Cited Count：8 Percentile：48.12(Chemistry, Analytical)

Journal Articles

Interaction of Fe $^{rm II}$ and Si under anoxic and reducing conditions; Structural characteristics of ferrous silicate co-precipitates

Francisco, P. C. M.; Mitsui, Seiichiro; Ishidera, Takamitsu; Tachi, Yukio; Doi, Reisuke; Shiwaku, Hideaki

Geochimica et Cosmochimica Acta, 270, p.1 - 20, 2020/02

https://doi.org/10.1016/j.gca.2019.11.009

Times Cited Count：23 Percentile：73.33(Geochemistry & Geophysics)

Oral presentation

Retention mechanisms of selenium in deep subsurface sedimentary formations in Horonobe area, Hokkaido, Japan

Dei, Shuntaro; Tachi, Yukio; Amano, Yuki; Sugiura, Yuki; Francisco, P. C. M.; Takahashi, Yoshio*

no journal, ,

Oral presentation

Se immobilization in pyrite by reaction with Fe(II) and polysulfides; Impacts of aging conditions

Francisco, P. C. M.; Shiwaku, Hideaki; Ishidera, Takamitsu; Tachi, Yukio

no journal, ,

The long-lived fission product Se-79 is a significant contributor to predicted radioactivity in geological repositories long after their closure. One possible retardation in repositories is by incorporation into Fe-sulfides like pyrite (FeS2). In this study, we clarify the role of polysulfides in the incorporation of Se into pyrite. Polysulfides are intermediate-oxidation sulfide species that are likely produced by diagenetic and microbial processes in repository host rocks. The present results show that reaction of Se(-II) with polysulfides resulted in the initial formation of elemental selenium. Aging at anoxic conditions led to the incorporation of Se into pyrite. These results highlight the role of polysulfides in retaining Se. We also investigate the effects of aging in air to determine the effects of changes in the redox conditions. The results show that oxidation did not affect Se retention.

Oral presentation

Effects of pH on the formation and transformation of Fe(II)-Si coprecipitates under anoxic, reducing conditions

Francisco, P. C. M.; Mitsui, Seiichiro; Ishidera, Takamitsu; Tachi, Yukio

no journal, ,

Oral presentation

Se(-II) immobilization in Fe(II)-(hydro)oxides; Coprecipitation and post-transformation behavior

Francisco, P. C. M.; Ishidera, Takamitsu; Tachi, Yukio

no journal, ,

Oral presentation

Retention mechanisms of selenium in deep sedimentary rocks from Horonobe, Hokkaido

Dei, Shuntaro; Tachi, Yukio; Amano, Yuki; Francisco, P. C. M.; Sugiura, Yuki; Takahashi, Yoshio*

no journal, ,

no abstracts in English

Oral presentation

Selenium reactions in ferrous and sulfide-rich environments; Effects of sulfide speciation

Francisco, P. C. M.; Ishidera, Takamitsu; Shiwaku, Hideaki; Kikuchi, Ryosuke*; Tachi, Yukio

no journal, ,

Oral presentation

Retention mechanisms of uranium in calcite veins from deep subsurface sedimentary formations of the Horonobe area, Hokkaido, Japan

Dei, Shuntaro; Sugiura, Yuki; Amano, Yuki; Francisco, P. C. M.; Takahashi, Yoshio*; Tachi, Yukio

no journal, ,

Uranium (U) is considered one of the important radionuclides for safety assessment of the geological disposal because U(VI) can form soluble carbonate complexes. Calcite is expected to precipitate as a secondary mineral in sedimentary rocks, and radionuclides migration may be retarded by incorporation into the calcite crystal structure. Although some laboratory experiments have reported U uptake by calcite, the distribution and chemical form of U in natural calcite is difficult to determine due to interference from coexisting elements. In this study, micro X-ray analyses were carried out on deep sedimentary rock samples to identify the distribution and chemical form of U in natural calcite.

Oral presentation

Impacts of Si on Se(IV) immobilization on ferrihydrite; An In-situ ATR-IR spectroscopic investigation

Francisco, P. C. M.; Tachi, Yukio

no journal, ,

Oral presentation

Selenide [Se(-II)] retention and mobilization in anoxic, iron-rich environments; Impacts of iron phase precipitation and transformation

Francisco, P. C. M.; Matsumura, Daiju; Kikuchi, Ryosuke*; Ishidera, Takamitsu; Tachi, Yukio

no journal, ,

Oral presentation

Selenium speciation in sedimentary formations from Horonobe, Hokkaido

Dei, Shuntaro; Miyakawa, Kazuya; Sasamoto, Hiroshi; Tachi, Yukio; Amano, Yuki; Francisco, P. C. M.; Sugiura, Yuki; Takahashi, Yoshio*

no journal, ,

no abstracts in English

Oral presentation

Se(-II, IV) interactions with Fe(II) species and phases under anoxic and reducing conditions

Francisco, P. C. M.; Kikuchi, Ryosuke*; Matsumura, Daiju; Shiwaku, Hideaki; Ishidera, Takamitsu; Tachi, Yukio

no journal, ,

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Selenide [Se(-II)] immobilization in anoxic, Fe(II)-rich environments; Coprecipitation and behavior during phase transformations

Certification of uranium isotope amount ratios in a suite of uranium ore concentrate certified reference materials

Impacts of Si on Se(IV) immobilization on ferrihydrite; An in situ ATR-IR spectroscopic study

Sorption behavior of selenide on montmorillonite

Interaction of Fe $^{rm II}$ and Si under anoxic and reducing conditions; Structural characteristics of ferrous silicate co-precipitates

Retention mechanisms of selenium in deep subsurface sedimentary formations in Horonobe area, Hokkaido, Japan

Se immobilization in pyrite by reaction with Fe(II) and polysulfides; Impacts of aging conditions

Effects of pH on the formation and transformation of Fe(II)-Si coprecipitates under anoxic, reducing conditions

Se(-II) immobilization in Fe(II)-(hydro)oxides; Coprecipitation and post-transformation behavior

Retention mechanisms of selenium in deep sedimentary rocks from Horonobe, Hokkaido

Selenium reactions in ferrous and sulfide-rich environments; Effects of sulfide speciation

Retention mechanisms of uranium in calcite veins from deep subsurface sedimentary formations of the Horonobe area, Hokkaido, Japan

Impacts of Si on Se(IV) immobilization on ferrihydrite; An In-situ ATR-IR spectroscopic investigation

Selenide [Se(-II)] retention and mobilization in anoxic, iron-rich environments; Impacts of iron phase precipitation and transformation

Selenium speciation in sedimentary formations from Horonobe, Hokkaido

Se(-II, IV) interactions with Fe(II) species and phases under anoxic and reducing conditions