Copper isotopic fractionation during adsorption on manganese oxide: Effects of pH and desorption

• Ijichi Yuta

  Department of Chemistry, Gakushuin University, Mejiro

• Ohno Takeshi

  Department of Chemistry, Gakushuin University, Mejiro

• Sakata Shuhei

  Department of Chemistry, Gakushuin University, Mejiro

抄録

We report new results for Cu²⁺ adsorption on δ-MnO₂ and the resulting changes in Cu isotopic composition due to isotopic fractionation. The adsorption experiments were designed as a pH series (3.22–6.94) and an adsorption-desorption series. ⁶³Cu adsorbs preferentially on δ-MnO₂, and the degree of isotopic fractionation is 0.45 ± 0.18‰ (2σ, n = 12). Preferential desorption of ⁶⁵Cu from δ-MnO₂ was also observed. The isotopic data are consistent with a closed isotopic equilibrium model, and the degree of fractionation indicates no systematic variation with pH or reaction time. Previously reported extended X-ray absorption fine structure study predicted the preferential adsorption of ⁶⁵Cu on δ-MnO₂, because of the formation of Cu²⁺ surface complexes (with 3–4 ligands) from dissolved Cu²⁺ (with 5 ligands); however, the opposite was observed in this study. The equilibrium in isotopic fractionation is affected by the bonding environment; hence, we suggest that dissolved Cu²⁺ species have a stronger bond than adsorbed ones.

収録刊行物

• ＧＥＯＣＨＥＭＩＣＡＬ　ＪＯＵＲＮＡＬ

  ＧＥＯＣＨＥＭＩＣＡＬ　ＪＯＵＲＮＡＬ 52 (2), e1-e6, 2018

  一般社団法人日本地球化学会

キーワード

• manganese oxide
• adsorption
• non-traditional isotope
• Cu isotope fractionation
• desorption

詳細情報

• CRID: 1390001204552130432
• NII論文ID: 130006708589
• NII論文ID: 40021815165
• NII書誌ID: AA00654975
• DOI: 10.2343/geochemj.2.0516
• ISSN: 18805973
• ISSN: 00167002
• NDL書誌ID: 029526176
• Web Site: http://id.ndl.go.jp/bib/029526176
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I029526176
• Web Site: https://www.jstage.jst.go.jp/article/geochemj/52/2/52_2.0516/_pdf
• 本文言語コード: en
• データソース種別:
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