Interactions of uranium with bacteria and kaolinite clay

Toshihiko Ohnuki, Takahiro Yoshida, Takuo Ozaki, Mohamad Samadfam, Naofumi Kozai, Kunio Yubuta, Toshiaki Mitsugashira, Takeshi Kasama, Arokiasamy J. Francis

研究成果: Contribution to journalArticle査読

51 被引用数 (Scopus)

抄録

We assessed the accumulation of uranium (VI) by a bacterium, Bacillus subtilis, suspended in a slurry of kaolinite clay, to elucidate the role of microbes on the mobility of U(VI). Various mixtures of bacteria and the koalinite were exposed to solutions of 8 × 10-6 M- and 4 × 10-4 M-U(VI) in 0.01 M NaCl at pH 4.7. After 48 h, the mixtures were separated from the solutions by centrifugation, and treated with a 1 M CH3COOK for 24 h to determine the associations of U within the mixture. The mixture exposed to 4 × 10-4 M U was analyzed by transmission electron microscope (TEM) equipped with EDS. The accumulation of U by the mixture increased with an increase in the amount of B. subtilis cells present at both U concentrations. Treatment of kaolinite with CH3COOK, removed approximately 80% of the associated uranium. However, in the presence of B. subtilis the amount of U removed was much less. TEM-EDS analysis confirmed that most of the U removed from solution was associated with B. subtilis. XANES analysis of the oxidation state of uranium associated with B. subtilis, kaolinite, and with the mixture containing both revealed that it was present as U(VI). These results suggest that the bacteria have a higher affinity for U than the kaolinite clay mineral under the experimental conditions tested, and that they can immobilize significant amount of uranium.

本文言語英語
ページ(範囲)237-243
ページ数7
ジャーナルChemical Geology
220
3-4
DOI
出版ステータス出版済み - 8 5 2005
外部発表はい

All Science Journal Classification (ASJC) codes

  • 地質学
  • 地球化学および岩石学

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