XAFSによる Ferrihydrite へのAs(V)共沈機構の考察  [in Japanese] XAFS Investigation for As(V) Co-Precipitation Mechanism with Ferrihydrite  [in Japanese]

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Author(s)

    • 所 千晴 TOKORO Chiharu
    • 早稲田大学理工学術院 創造理工学部 環境資源工学科 Department of Resources and Environmental Engineering, School of Creative Science and Engineering, Faculty of Science and Engineering, Waseda University
    • 古賀 創 KOGA Hajime
    • 早稲田大学大学院 創造理工学研究科 地球・環境資源理工学専攻 Department of Resources and Environmental Engineering, School of Creative Science and Engineering, Faculty of Science and Engineering, Waseda University
    • 小田 祐史 [他] ODA Yuji
    • 早稲田大学大学院 創造理工学研究科 地球・環境資源理工学専攻 Department of Resources and Environmental Engineering, School of Creative Science and Engineering, Faculty of Science and Engineering, Waseda University
    • 大和田 秀二 OWADA Shuji
    • 早稲田大学理工学術院 創造理工学部 環境資源工学科 Department of Resources and Environmental Engineering, School of Creative Science and Engineering, Faculty of Science and Engineering, Waseda University
    • 高橋 嘉夫 TAKAHASHI Yoshio
    • 広島大学大学院 理学研究科 地球惑星システム学専攻 Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University

Abstract

XRD/XAFS analysis were conducted to investigate the As(V) co-precipitation mechanism with ferrihydrite (γ-FeOOH). In As(V) co-precipitation with ferrihydrite, XRD results showed that As(V) complexation to the surface of ferrihydrite was dominant when the initial molar ratio of As/Fe was less than 0.25, whereas surface precipitation of amorphous ferric arsenate was formed when the initial molar ratio of As/Fe was more than 0.5.<BR>Both of XANES and EXAFS analysis on K-edge of As showed As(V) co-precipitates with ferrihydrite was the mixture of As(V) adsorbed ferrihydrite and amorphous ferric arsenate. Molar ratio of amorphous ferric arsenate in As(V) co-precipitates was estimated to be more than 0.5 when the initial molar ratio of As/Fe was more than 0.5. These results are in good agreement with the XRD results. EXAFS analysis assuming one surface complex for As-Fe bond showed the coordination number of As to Fe in As(V) co-precipitates increased with increasing the initial molar ratio of As/Fe. Moreover, EXAFS analysis assuming three kinds of surface complexes for As-Fe bond showed the coordination number for 2.85 Å of the atomic distance of As-Fe increased and it for 3.24 Å of the atomic distance of As-Fe decreased with increasing the initial As/Fe molar ratio. All experimental data obtained in this study showed As(V) co-precipitation mechanism shifted gradually from As(V) complexation to the surface of ferrihydrite toward amorphous ferric arsenate with increase in the initial molar ratio of As/Fe.

Journal

  • Journal of MMIJ

    Journal of MMIJ 127(4), 213-218, 2011-03-25

    The Mining and Materials Processing Institute of Japan

References:  19

Codes

  • NII Article ID (NAID)
    10028160391
  • NII NACSIS-CAT ID (NCID)
    AA12188381
  • Text Lang
    JPN
  • Article Type
    ART
  • ISSN
    18816118
  • NDL Article ID
    11069251
  • NDL Source Classification
    ZP41(科学技術--金属工学・鉱山工学)
  • NDL Call No.
    Z17-315
  • Data Source
    CJP  NDL  J-STAGE 
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