2011A1676            

BL14B2

ከᏍ㉁㓟໬㕲⢏Ꮚࡢ◉㓟࢖࢜ࣥ྾╔≧ែゎᯒ
Adsorption State Analysis of Arsenate Ions on the Surface ofPorous Ferric-Oxide Particles Synthesized by Novel Solution Process⠛⏣ ᘯ㐀 a, ⸨ᯞ ಇ a, ⸨⏣ ဴ㞝 b, 㕥ᮌ ⱱ aKozo Shinodaa, Shun Fujiedaa, Tetsuo Fujitab, Shigeru Suzukiaaᮾ໭኱Ꮫ, bDOWA ࣓ࢱ࣐ࣝ࢖ࣥ㻔ᰴ㻕 Tohoku University, bDowa Metals & Mining Co. Ltd.
a㠀㕲〇㘐ᗫᲠ≀ฎ⌮㐣⛬࡛⏕ᡂࡍࡿ◉㓟㕲ࢆཎᩱ࡜ࡋ࡚ᚓࡽࢀࡿ㓟໬㕲⢏Ꮚࡣࠊ኱ẚ⾲㠃✚࡜ඃࢀࡓỿ㝆ᛶࢆ♧ࡍከᏍᛶ㉸ᚤ⢏Ꮚ㞟ྜయ࡛࠶ࡾࠊࡑࡢ≉ᚩࢆά࠿ࡋ࡚Ỉ⎔ቃ୰࡟࠾ࡅࡿ໬Ꮫ✀ศ㞳㝖ཤ⏝྾╔ᮦ࡬ࡢ㐺⏝ࢆ┠ᣦࡋ࡚࠸ࡿࠋAs K ྾཰➃࡛ࡢ⺯ග཰㔞 X ⥺྾཰ศග ᐃࢆᐇ᪋ࡋ࡚ࠊᕼⷧ⁐ᾮ୰࡛⢏Ꮚ⾲㠃࡟྾╔ࡋࡓ◉㓟࢖࢜ࣥࡢ྾╔ᙧែࢆㄪ࡭ࡓࠋ⤖ᯝࠊྠᵝࡢᒁᡤཎᏊ㓄ิᵓ㐀ࢆ᭷ࡍࡿ㓟໬㕲⢏Ꮚࡢሙྜ࡜␗࡞ࡿᵝᘧ࡛◉㓟࢖࢜ࣥࡀ⾲㠃྾╔ࡋ࡚࠸ࡿࡇ࡜ࢆぢฟࡋࡓࠋ࣮࣮࢟࣡ࢻ㸸 Ỉ㉁ಖ඲ࠊỈί໬ࠊ᭷ᐖ໬Ꮫ✀྾╔㝖ཤࠊX ⥺྾཰ศගἲ⫼ᬒ࡜◊✲┠ⓗ㸸㠀㕲〇㘐㐣⛬࡛᤼ฟࡉࢀࡿ⃰ཌ◉㓟⁐ᾮ࠿ࡽ As ࢆᅛᐃ໬ฎ⌮ࡍࡿ㝿࡟⏕ᡂࡍࡿ◉㓟㕲 scorodite,FeAsO4㺃2H2O ࡣࠊ⤖ᬗᛶࡀ㧗ࡃ⢏ᚄࡶⰋࡃᥞࡗࡓࣘࢽ࣮ࢡ࡞⢏Ꮚ⢊ᮎ࡛࠶ࡿ[1]ࠋࡇࡢ㧗⤖ᬗᛶ኱⢏ᚄ scorodite ࡣ㏻ᖖࡢ Fe㻔III㻕-As㻔V㻕ඹỿ཯ᛂ࡟ࡼࡿྜᡂἲ࡜ࡣ␗࡞ࡾࠊFe㻔II㻕࠿ࡽ Fe㻔III㻕࡬ࡢ㓟໬ᚋඹỿࡉࡏࡿ཯ᛂࣉࣟࢭࢫࢆ฼⏝ࡋ࡚స〇ࡉࢀࡿࠋࡑࡋ࡚ pH4-5 ࡢ⁐ᾮ୰࡛ࡣᴟࡵ࡚⁐ゎᗘࡀప
ࡃࠊAs ࡟ᑐࡍࡿ⪏⁐ฟᛶ࡟ඃࢀ࡚࠸ࡿࠋ୍᪉ࠊᙉሷᇶᛶỈ⁐ᾮ୰࡛ࡣ⁐ゎᗘࡀ㧗ࡃ࡞ࡿࡀࠊࡓ࡜࠼ࡤ NaOH 20g/L㻔0.5mol/L㻕௨ୖࡢሷᇶᛶ⁐ᾮ୰࡛ࡣ㏿ࡸ࠿࡟⁐ゎࡍࡿࡀࠊྠ᫬࡟㓟໬㕲ࡀ෌ᯒฟࡍࡿࠋࡇࡢ㓟໬㕲⢏Ꮚࡣࠊࢼࣀ⢏Ꮚ⢊ᮎ࡟༉ᩛࡍࡿẚ⾲㠃✚ࢆ᭷ࡍࡿࠊཎᩱ⢏Ꮚࡢ⢏ᚄᩘ༑ȣmእᙧࢆ⥔ᣢࡋࡓከᏍ㉁ᙧ≧࡛ࠊඃࢀࡓỿ㝆ᛶࢆ♧ࡍࠋࡇࡢࡼ࠺࡞ከᏍᛶ㓟໬㕲⢏ᏊࡣࠊỈ⎔ቃ୰࡟࠾ࡅࡿ໬Ꮫ✀ศ㞳㝖ཤ⏝྾╔ᮦ࡟㐺ࡍࡿ࡜⪃࠼ࡽࢀࡿࠋ2010B1 ᮇ㔜Ⅼ⏘ᴗ฼⏝ㄢ㢟㸦ㄢ㢟␒ྕ2010B1851㸧࡟࠾࠸࡚ࠊBL14B2 ࢆ฼⏝ࡋࡓ X ⥺྾཰ศග ᐃᐇ㦂ࢆᐇ᪋ࡋࠊࡇࡢከᏍᛶ㓟໬㕲⢏Ꮚࡀ maghemite, J-Fe2O3 㢮ఝࡢᒁᡤཎᏊ㓄ิᵓ㐀ࢆ᭷ࡍࡿࡇ࡜ࡀ☜ㄆࡉࢀࡓࠋࡲࡓࠊpH ᮲௳ࡢ␗࡞ࡿ◉㓟⁐ᾮ୰࡛⢏Ꮚ⾲㠃࡟྾╔ࡉࢀࡓ◉㓟࢖࢜ࣥࡢ྾╔ᙧែࢆㄪ࡭ࡿࡓࡵ࡟ As K ྾཰➃࡟࠾࠸࡚⺯ග཰㔞 X ⥺྾཰ศග ᐃࢆᐇ᪋ࡋࡓࡀࠊከᏍᛶ㓟໬㕲⢏Ꮚ࡜ẚ㍑ヨᩱ࡛࠶ࡿ maghemite ࣂࣝࢡ⢏Ꮚ㛫ࠊࡲࡓ྾╔ᾮࡢ pH ᮲௳࡟ࡼࡿᕪ␗ࢆヲ⣽࡟㆟ㄽ࡛ࡁࡿရ㉁ࡢࢫ࣌ࢡࢺࣝࢆᚓࡿࡇ࡜ࡀ࡛ࡁ࡞࠿ࡗࡓࠋᮏᐇ㦂࡛ࡣࠊAs K ྾཰➃࡟࠾࠸࡚⺯ග཰㔞 X ⥺྾཰ศග ᐃࢆᐇ᪋ࡋࠊᕼⷧ⁐ᾮ୰࡛⢏Ꮚ⾲㠃࡟྾╔ࡋࡓ◉㓟࢖࢜ࣥࡢ྾╔ᙧែࢆㄪ࡭ࡿࡇ࡜ࠊࡑࡋ࡚⢏Ꮚ⾲㠃ࡢ྾╔◉㓟࢖࢜ࣥࢆሷᇶᛶ⁐ᾮ࡟ࡼࡗ࡚⬺╔ࡉࡏࡓᚋ࡟ṧ␃ࡍࡿ྾╔◉㓟࢖࢜ࣥࡢ྾╔ᙧែ࡜ࡢẚ㍑࠿ࡽࠊ◉㓟࢖࢜ࣥࡢ྾⬺╔ᶵᵓ࡟ࡘ࠸࡚ࡢ▱ぢࢆᚓࡿࡇ࡜ࢆ┠ⓗ࡜ࡍࡿࠋࡉࡽ࡟ࠊ㌿᥮㟁Ꮚ཰㔞ἲ㻔Conversion Electron Yield,CEY㻕ࢆ Fe K ྾཰➃࡟࠾ࡅࡿ X ⥺྾཰ศග ᐃ࡟㐺⏝ࡋ࡚ࠊ㓟໬㕲⢏Ꮚ⾲㠃ࡢᒁᡤᵓ㐀ࡀ◉㓟࢖࢜ࣥࡢ྾⬺╔࡟ࡼࡗ࡚࡝ࡢࡼ࠺࡟ኚ໬ࡍࡿ࠿ࢆㄪ࡭ࡿࡇ࡜࡜ࡋࡓࠋᐇ㦂㸸࠙ ᐃヨᩱస〇ࠚ㧗⤖ᬗᛶ኱⢏ᚄ scorodite ⢏ᏊࢆฟⓎཎᩱ࡜ࡋࠊࡇࢀࢆᙉሷᇶᛶ NaOH Ỉ⁐ᾮ࡟ᢞධࡋ୍࡚ᐃ᫬㛫཯ᛂࡉࡏᚓࡽࢀࡓ⢏Ꮚࢆᅇ཰ࠊὙί࠾ࡼࡧ஝⇱ࡋ࡚ࠊከᏍᛶ㓟໬㕲⢏Ꮚࢆᚓࡓࠋヨᩱ୰ࡢṧ␃As ⃰ᗘࡣ 0.1mass%⛬ᗘ࡛࠶ࡿࠋBET ẚ⾲㠃✚ࡣ 239m2/g ࡛࠶ࡗࡓࠋẚ㍑ヨᩱ࡜ࡋ࡚࢜࢟ࢩỈ㓟໬㕲 lepidocrocite, J-FeOOH ࢆ኱Ẽ୰⇕ฎ⌮ࡋ࡚ᚓࡽࢀࡿࣂࣝࢡ
maghemite ⢏Ꮚࢆ⏝ពࡋࡓࠋ࠙As ྾╔ᐇ㦂ࠚከᏍᛶ㓟໬㕲⢏Ꮚ࠾ࡼࡧ maghemite ཧ↷ヨᩱ⢏Ꮚ࡟ᑐࡋ࡚ࠊ௨ୗࡢᡭ㡰࡛ As ྾╔ヨ㦂ࢆᐇ᪋ࡋࡓࠋ20mg/L ◉㓟⁐ᾮࡢ pH ࢆ 5 ࡟ㄪᩚࡋࠊ⁐ᾮ 200mL ࡟⢏Ꮚࢆ 40mg ᢞධࡋࠊ4 ᫬㛫྾╔ࡉࡏᅇ཰ࡍࡿࠋ྾╔ᾮ୰࡟ṧ␃ࡋࡓ As ⃰ᗘࡢ ICP-AES ศᯒ್࠿ࡽ྾╔㔞ࢆồࡵࡿ࡜ࠊከᏍᛶ㓟໬㕲ࡣ
42.0mg-As/gࠊmaghemite ཧ↷ヨᩱࡣ 15.6mg-As/g ࡛࠶ࡗࡓࠋ
࠙As ⬺╔ᐇ㦂ࠚ
pH5 ࡢሙྜࡼࡾࡶ◉㓟࢖࢜ࣥ྾╔㔞ࡢከ࠸ pH3 ࡢ᮲௳࡛◉㓟࢖࢜ࣥࢆ྾╔ࡉࡏࡓ⢏Ꮚ㸦྾╔㔞ࡣከᏍᛶ㓟໬㕲࡛ 92.4mg/gࠊmaghemite ཧ↷ヨᩱ࡛ 23.5mg/g㸧ࢆࠊpH10 ࡟ㄪᩚࡋࡓ NaOH Ỉ⁐ᾮ࡟ 200mg ᢞධࡋࠊ4 ᫬㛫ᨩᢾࡋࡓ࠶࡜⢏Ꮚࢆᅇ཰ࡋࡓࠋ⬺╔㔞ࡣࠊ⬺╔ヨ㦂⤊஢ᚋ⁐ᾮ୰ࡢ As⃰ᗘ࠿ࡽồࡵࡓࠋከᏍᛶ㓟໬㕲ࡣ⬺╔⋡ࡀ⣙ 11%࡛ 82.2mg/gࠊAs ࡀṧ␃ࠊࡑࡋ࡚ maghemite ཧ↷ヨᩱ࡛ࡣ⬺╔⋡⣙ 21%࡛ࠊ18.5mg/g ࡢ As ࡀ⢏Ꮚ⾲㠃࡟ṧ␃ࡋ࡚࠸ࡓࠋ࠙X ⥺྾཰ศග ᐃࠚFe K ྾཰➃࡟࠾ࡅࡿ㌿᥮㟁Ꮚ཰㔞࣮ࣔࢻ ᐃࠊ࠾ࡼࡧ As K ྾཰➃࡟࠾ࡅࡿ⺯ග཰㔞࣮ࣔࢻ
ᐃࡣࠊBL14B2 ࡛ᐇ᪋ࡋࡓࠋ⤖ᯝ࠾ࡼࡧ⪃ᐹ㸸
Fig.1 ࡟ࠊAs K ྾཰➃࡛ᐃࡋࡓつ᱁໬ XANES ࢫ࣌ࢡࢺࣝࢆ♧ࡍࠋ

Fig.1 As K ྾཰➃࡛ᐃࡋࡓྛヨᩱࡢ XANES ࢫ࣌ࢡࢺࣝ ◉㓟㕲ࡢࡼ࠺࡞໬ྜ≀ࢆᙧᡂࡋ࡚࠸ࡿሙྜࡸᙉ࠸つ๎ᛶ┦㛵ࡀ࠶ࡿሙྜ࡟ࡣࠊ྾཰➃┤ୖࡢ㗦࠸྾཰ࣆ࣮ࢡ㻔white line㻕ࡢ㧗࢚ࢿࣝࢠ࣮ഃ࡟ᚤ⣽ᵓ㐀ࡀ⌧ࢀࡿࠋཧ↷ヨᩱ⾲㠃࡟྾╔ࡋࡓ As ࡟ᑐࡋ࡚ࡣᅗ୰▮༳࡛♧ࡍࡼ࠺࡞つ๎ᛶ┦㛵ࢆ♧ࡍᑠࡉ࡞ࣆ࣮ࢡࡀほ ࡉࢀࡓࡀࠊከᏍᛶ㓟໬㕲ࡢሙྜࡣẚ㍑ⓗ༢⣧࡞ࢫ࣌ࢡࢺࣝᙧ≧ࢆ♧ࡋࡓࠋࡇࢀࡣࠊከᏍᛶ㓟໬㕲࡟྾╔ࡋࡓ◉㓟࢖࢜ࣥ୰ࡢ Asࡀࠊ⢏Ꮚ⾲㠃ࡢ Fe ࠶ࡿ࠸ࡣ FeO6 ඵ㠃య࡜ࡢ┦㛵ࡀᙅ࠸࠿ࠊ┦㛵㊥㞳࡟ࡤࡽࡘࡁࡀ࠶ࡿࡇ࡜ࢆ♧ࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋ
ḟ࡟ࠊྛヨᩱ࡟ᑐࡍࡿ EXAFS ࢫ࣌ࢡࢺࣝࡢ Fourier ኚ᥮ࢆ Fig.2 ࡟♧ࡍࠋ2010B ᮇࡢᐇ㦂࡛ࡣࠊ
Fourier ኚ᥮࡟౪ࡍࡿ EXAFS ࢫ࣌ࢡࢺࣝࡢ⠊ᅖࡀࠊἼᩘ k ࡛᭱኱ 12Å-1 ࡲ࡛࡛࠶ࡾࠊ➨஧㏆᥋┦㛵ࢆヲ⣽࡟㆟ㄽࡍࡿ࡟ሓ࠼ࡿရ㉁࡜ࡣ࠸࠼࡞࠿ࡗࡓࠋᮏᐇ㦂࡛ࡣࠊk = 14 Å-1 ࡲ࡛࡜ࡍࡿࡇ࡜ࡀ࡛ࡁࡓࠋ➨୍㏆᥋┦㛵ࡣࠊ◉㓟࢖࢜ࣥ AsO43- ࡢ As-O ࣌࢔࡟ᑐᛂࡋࠊAs ࡀᖖ࡟ࡇࡢᅄ㠃యᵓ㐀ࣘࢽࢵࢺ࡛Ꮡᅾࡍࡿࡇ࡜࡟ࡼࡾ࠸ࡎࢀࡢヨᩱ࡛ࡶཎᏊ㛫㊥㞳ࡣ࡯ࡰ➼ࡋ࠸ࠋ୍᪉ࠊ◉㓟࢖࢜ࣥࡢ㓟⣲ࢆ௓ࡋࡓእ㒊࡜ࡢ┦㛵ࢆ♧ࡍ➨஧㏆᥋ࣆ࣮ࢡᙧ≧ࡣࠊᅗ୰▮༳࡛♧ࡍࡼ࠺࡟ከᏍᛶ㓟໬㕲ࡢሙྜ࡜ཧ↷ヨᩱ࡜࡛␗࡞ࡗ࡚࠸ࡿࡇ࡜ࡀࢃ࠿ࡿࠋẚ㍑ࡢࡓࡵ࡟◉㓟㕲 scorodite ⤖ᬗࡢࢹ࣮ࢱࢆ୪࡭࡚♧ࡋ࡚࠸ࡿࡀࠊᅗ୰▮༳࡛♧ࡍࡼ࠺࡟ࠊ◉㓟㕲୰ࡢ As-O-Fe ┦㛵࡟ᑐᛂࡍࡿ఩⨨࡜ࠊࡑࢀࡼࡾ㏆㊥㞳ࡢࣆ࣮ࢡࡀほ ࡉࢀࡿࠋཧ↷ヨᩱ࡛ࡣࡇࢀࡽ 2 ࡘࡢ┦㛵ࣆ࣮ࢡࡀ୧᪉ほ ࡉࢀࡿࡢ࡟ᑐࡋ࡚ࠊ
ከᏍᛶ㓟໬㕲࡛ࡣ࡯࡜ࢇ࡝㏆㊥㞳ഃࡢࣆ࣮ࢡࡢࡳࡀほ ࡉࢀ࡚࠸ࡿࠋ࢜࢟ࢩỈ㓟໬㕲ࡸࠊ
ferrihydrite ࡜࿧ࡤࢀࡿ FeO6 ඵ㠃యࢆࣘࢽࢵࢺ࡜ࡍࡿ⤖ᬗᵓ㐀ࢆࡶࡘᅛయ⾲㠃࡛ࡢ◉㓟࢖࢜ࣥ྾╔࡟࠾࠸࡚ࠊ࠸ࡃࡘ࠿ࡢ྾╔ᵝᘧࡀᥦၐࡉࢀ࡚࠾ࡾ[2]ࠊ㊥㞳ࡀ㏆࠸ࡶࡢࡣ FeO6 ඵ㠃య࡜ AsO4 ᅄ㠃యࡀ 2 ಶࡢ O ࢆඹ᭷㸦஫࠸ࡢ⛸ࢆඹ᭷㸧ࡍࡿሙྜ࡛⣙ 3.12 Åࠊ1 ಶࡢ O ࡢࡳࢆඹ᭷㸦㡬Ⅼඹ᭷㸧ࡍࡿሙྜ࡛ࡣ As-O-Fe ゅ࡟ࡼࡿࡀ᭱኱ 3.65 Å ⛬ᗘ࡜ࡉࢀ࡚࠸ࡿࠋscorodite ⤖ᬗ୰࡟࠾࠸࡚ࡶᖖ࡟
ඵ㠃య࡜ᅄ㠃యࡣ㡬Ⅼඹ᭷ࡢᙧࢆ࡜ࡗ࡚࠸ࡿࠋࡇࢀࢆཧ⪃࡟ࡍࢀࡤࠊmaghemite ཧ↷ヨᩱ⢏Ꮚ࡟྾╔ࡍࡿ◉㓟࢖࢜ࣥࡢከࡃࡣ㡬Ⅼඹ᭷ࡋ࡚࠸ࡿࡀࠊከᏍᛶ㓟໬㕲⢏Ꮚ࡟ᑐࡋ࡚ࡣࠊ኱㒊ศࡀ⛸ඹ᭷ࡢᙧ࡛྾╔ࡋ࡚࠸ࡿ࡜࠸࠺ࡇ࡜࡟࡞ࡿࠋ୍ᗘ྾╔ࡉࡏࡓᚋ࡟ሷᇶᛶ⁐ᾮ୰୍࡛㒊ࡀ⬺╔ࡋࠊࡑࢀ࡛ࡶṧ␃ࡋࡓ྾╔◉㓟࢖࢜ࣥࡢ྾╔ᵝᘧࡣࠊ⬺╔๓࡜࡯ࡰ➼ࡋ࠸ࡼ࠺࡟ぢ࠼ࡿࠋࡓࡔࡋࠊ྾╔㔞࡟ᑐࡋ࡚⬺╔⋡ࡀ 10㹼20%⛬ᗘ࡜ప࠸ࡢ࡛ࠊほ ࡉࢀࡿ྾╔ᵝᘧ࡟኱ࡁ࡞ኚ໬ࡀ࡞ࡃ࡜ࡶ୙ᛮ㆟࡛ࡣ࡞࠸ࠋࡋ࠿ࡋ࡞ࡀࡽࠊᑡ࡞ࡃ࡜ࡶࡇࡢࡼ࠺࡞྾╔ᵝᘧࡢ㐪࠸ࡀ⬺╔⋡࡟㛵㐃ࡋ࡚࠸ࡿࡇ࡜ࢆ♧၀ࡋ࡚࠸ࡿ࡜⪃࠼࡚Ⰻࡉࡑ࠺࡛࠶ࡿࠋࡓࡔࡋࠊ⣽Ꮝࡀ࡯࡜ࢇ࡝Ꮡᅾࡋ࡞࠸ཧ↷ヨᩱ࡜ከᩘࡢ
⣽Ꮝࢆ᭷ࡍࡿከᏍᛶ㓟໬㕲ࡢᙧ≧ࡢ㐪࠸ࡀ㛵ಀࡋ࡚࠸ࡿྍ⬟ᛶࡶ⪃࠼ࡽࢀࡿࡢ࡛ࠊ⣽Ꮝࢧ࢖ࢬศᕸ࡜྾⬺╔㔞࠾ࡼࡧ྾╔ᙧែࡢ㐪࠸࡞࡝ࡉࡽ࡞ࡿ᳨ウࡀᚲせ࡛࠶ࡿࠋFig.2 As K ྾཰➃࡟࠾ࡅࡿ EXAFS ࢫ࣌ࢡࢺࣝࡢ Fourier ኚ᥮ḟ࡟ࠊFe K ྾཰➃࡛㌿᥮㟁Ꮚ཰㔞ἲ࡟ࡼࡾ ᐃࡋࡓ maghemite ཧ↷ヨᩱࡢ⾲㠃ᩄឤ EXAFS ࢫ࣌ࢡࢺࣝࢆ Fig.3 ࡟♧ࡍࠋ㌿᥮㟁Ꮚ཰㔞࣮ࣔࢻࡣ⾲㠃ᩄឤ࡞ᡭἲ࡛࠶ࡿࡀࠊࡇࡢධᑕ X ⥺࢚ࢿࣝࢠ࣮㡿ᇦ࡛ࡣࠊศᯒ῝ࡉࡣ⾲㠃࠿ࡽᑡ࡞ࡃ࡜ࡶ 50㹼60nm ⛬ᗘ࡜⪃࠼ࡽࢀࡿࡢ࡛ࠊ྾╔ࡋࡓ◉㓟࢖࢜ࣥ࡜ࡢ┦஫స⏝ࢆ♧ࡍࢫ࣌ࢡࢺࣝᙧ≧ࡢኚ໬ࢆ᳨ฟࡍࡿࡇ࡜ࡣᅔ㞴࡛࠶ࡿࠋࡲࡓࠊ≉࡟ከᏍᛶ㓟໬㕲⢏Ꮚ࡟࠾࠸࡚ࡣ⢏Ꮚෆ࡟ከࡃࡢ✵㝽ࡀᏑᅾࡋࠊ⢏ᚄࡶᩘ༑ȣm ࡜኱ࡁ࠸ࡓࡵ࡟ࠊヨᩱࡑࡢࡶࡢࢆ㟁ᴟ࡜ࡋ࡚㟁఩ᕪࢆ༳ຍࡍࡿࡇࡢᡭἲ࡛ࡣ㔜せ࡞ࠊヨᩱࡢᑟ㟁ᛶࢆ☜ಖࡍࡿࡇ࡜ࡀᅔ㞴࡛࠶ࡿࠋࡇࢀࡀせᅉ࡜࡞ࡗ࡚ࠊほ ࡉࢀࡿࢫ࣌ࢡࢺࣝ࡟ࣀ࢖ࢬࡀ஌ࡗࡓࡾࠊࢫ࣌ࢡࢺࣝᙧ≧ࡀṍࢇࡔࡾࡍࡿྍ⬟ᛶࡀ࠶ࡿࠋከᏍᛶ㓟໬㕲⢏Ꮚ࡟ᑐࡋ࡚ᐇ᪋ࡋࡓ ᐃࡢ⤖ᯝᚓࡽࢀࡓࢫ࣌ࢡࢺࣝࡣࠊ
᣺ᖜࡀᑠࡉࡃ࡞ࡾ S/N ẚࡶᝏࡃṧᛕ࡞ࡀࡽ⾲㠃ᒁᡤᵓ㐀ࢆ⪃ᐹࡍࡿࡇ࡜ࡣ࡛ࡁ࡞࠿ࡗࡓࠋFig.3 ࡟♧ࡋࡓࢫ࣌ࢡࢺࣝᙧ≧ࡶ᣺ᖜࡀᑠࡉࡃⱝᖸṍࢇ࡛࠸ࡿྍ⬟ᛶࡣ࠶ࡿࡀࠊas-synthesized ヨᩱ࡟࠾࠸࡚ࠊ⢏Ꮚෆ㒊ࡢᒁᡤᵓ㐀ࢆ཯ᫎࡋࡓ㏱㐣ࢫ࣌ࢡࢺࣝ࡟ᑐࡋ࡚⾲㠃ࢆ཯ᫎࡍࡿ㌿᥮㟁Ꮚ཰㔞ࢫ࣌ࢡࢺࣝࡀ␗࡞ࡾࠊࡈࡃ⾲㠃㡿ᇦ࡛ࡣ➨஧㏆᥋㡿ᇦࡢཎᏊ㓄ิࡀ␗࡞ࡗ࡚࠸ࡿྍ⬟ᛶࡀ♧၀ࡉࢀࡿࠋࡇࡢ⾲㠃࡟≉␗࡞ᵓ㐀ࡣࠊ◉㓟࢖࢜ࣥࢆ྾╔ࡋࡓᚋࡶ࡯࡜ࢇ࡝ኚ໬ࡋ࡞࠸ࡀࠊ⬺╔ヨ㦂ᚋ࡟ࡣኚ໬ࡀぢࡽࢀࠊ⢏Ꮚෆ㒊ࡢᵓ㐀࡟㏆ࡃ࡞ࡗ࡚࠸ࡿࡼ࠺࡟ぢ࠼ࡿࠋࡑࡢ⌮⏤࡜ࡋ࡚⪃࠼ࡽࢀࡿࡢࡣ௨ୗࡢࡼ࠺࡞ࡶࡢ࡛࠶ࡿࠋ⾲㠃࡟Ḟ㝗ࡀᏑᅾࡋࠊࡑࡇ࡟◉㓟࢖࢜ࣥࡀ㡬Ⅼඹ᭷࡛྾╔ࡍࡿࠋࡇࡢ࡜
ࡁ Fe ࠿ࡽぢࡓ⎔ቃᵓ㐀࡟ࡣᙳ㡪ࡣ࡞࠸ࠋࡑࡋ࡚ሷᇶᛶ⁐ᾮ୰࡛ࡢ⬺╔ࣉࣟࢭࢫࡢ㝿࡟⬺╔ࡍࡿ◉㓟࢖࢜ࣥ࡜࡜ࡶ࡟Ḟ㝗㡿ᇦࡢ Fe ࡀ⁐ฟࡋࠊẚ㍑ⓗ㓄ิࡢᩚࡗࡓ⢏Ꮚෆ㒊ࡢᵓ㐀ࡀ⾲㠃࡟⌧ࢀࡿࠋ

Fig.3 ཧ↷ヨᩱࡢ㏱㐣 ᐃ⤖ᯝ࠾ࡼࡧ྾╔๓࡜྾⬺╔ᚋࡢ⢏Ꮚ⾲㠃࡟࠾ࡅࡿᒁᡤᵓ㐀ኚ໬ࢆ♧ࡍ㌿᥮㟁Ꮚ཰㔞 ᐃ⤖ᯝࡢ Fe K ྾཰➃ EXAFS ࢫ࣌ࢡࢺࣝ࠾ࡼࡧࡑࡢ Fourier ኚ᥮ඖ᮶⁐ᾮࣉࣟࢭࢫ࡛స〇ࡍࡿከᏍᛶ㓟໬㕲⢏Ꮚ࡟࠾࠸࡚ࡣࠊࡑࡢ⾲㠃ࡣḞ㝗ࡀᏑᅾࡍࡿ࡜࠸࠺ࡼࡾࡣࡴࡋࢁ⤖ᬗᵓ㐀ࡢ኱ࡁࡃᔂࢀࡓ㠀ᬗ㉁ᵝࡢᵓ㐀࡜⪃࠼ࡽࢀࡿࠋᚑࡗ࡚ࠊ◉㓟࢖࢜ࣥࡀ⛸ඹ᭷࡛྾╔ࡍࡿẚ⋡ࡀ㧗ࡃࠊ⬺╔⋡ࡶཧ↷ヨᩱ࡜ẚ㍑ࡋ࡚పࡃ࡞ࡿ࡜⪃࠼ࡿࡇ࡜ࡶ࡛ࡁࡿࠋࡓࡔࡋࠊከᏍᛶ㓟໬㕲⢏Ꮚࡣࠊࢼࣀࢧ࢖ࢬࡢ㠀ᖖ࡟ᚤ⣽࡞⢏Ꮚࡀจ㞟ࡋ࡚ᵓᡂࡉࢀ࡚࠸ࡿࡢ࡛ࠊ⢏ᚄࡀ㌿᥮㟁Ꮚ཰㔞ἲ࡟࠾ࡅࡿ᳨ฟ῝ࡉᮍ‶࡜࡞ࡿྍ⬟ᛶࡀ㧗࠸ࠋᚑࡗ࡚ࠊ㌿᥮㟁Ꮚ཰㔞ἲ࡛⾲㠃࡜ෆ㒊ࡢᵓ㐀᝟ሗࢆศ㞳ࡍࡿࡇ࡜ࡣᅔ㞴࠿ࡶࡋࢀ࡞࠸ࠋ௒ᚋࡢㄢ㢟㸸௒ᅇࡢᐇ㦂࡛ࡣࠊ◉㓟࢖࢜ࣥࡢ྾╔≧ែࢆࡼࡾヲ⣽࡟⪃ᐹ࡛ࡁࡿရ㉁ࡢࢫ࣌ࢡࢺࣝࢆᚓࡿࡇ࡜ࡀ࡛ࡁࡓࠋࡋ࠿ࡋࠊ྾╔㔞࡟ᑐࡋ࡚⬺╔㔞ࡀᑡ࡞ࡃࠊ྾╔ᚋࡑࡋ࡚⬺╔ᚋࡢṧ␃◉㓟࢖࢜ࣥ࿘ᅖࡢ⎔ቃᵓ㐀ࢆṇࡋࡃ཯ᫎࡋ࡚࠸࡞࠸ྍ⬟ᛶࡀ࠶ࡿࠋࡲࡓࠊ◉㓟࢖࢜ࣥࡢ྾╔≧ែࢆ⪃࠼ࡿୖ࡛㔜せ࡞⢏Ꮚ⾲㠃࡛ࡢ◉㓟࢖࢜ࣥ྾╔ࡀཬࡰࡍ Fe ࿘ᅖࡢ⎔ቃᵓ㐀ኚ໬ࢆ㆟ㄽࡍࡿࡓࡵ࡟ࡣࠊࡸࡣࡾ㌿᥮㟁Ꮚ཰㔞 ᐃ࡟ࡼࡾရ㉁ࡢ㧗࠸ࢫ࣌ࢡࢺࣝࢆᚓࡿࡇ࡜ࡀ୙ྍḞ࡛࠶ࡿࠋࡇࢀࡽ⌧ᅾࡢᐇ㦂ᡭἲⓗㄢ㢟ࢆඞ᭹ࡍࡿ࡜࡜ࡶ࡟ࠊ◉㓟࢖࢜ࣥ྾╔ᶵᵓࡢࡉࡽ࡟῝࠸⌮ゎ࡜ࠊࡑࢀ࡟ᇶ࡙ࡃ྾╔ᮦ࡜ࡋ࡚ࡢ⢏Ꮚ⾲㠃ᙧែࠊᵓ㐀ࡢタィ࡜ไᚚࡀ௒ᚋࡢㄢ㢟࡛࠶ࡿࠋཧ⪃ᩥ⊩㸸[1] T. Fujita, R. Taguchi, M. Abumiya, M. Matsumoto, E. Shibata, T. Nakamura, Hydrometallurgy, 90, 92
㻔2008㻕.
[2] G. A. Waychunas, B. A. Rea, C. C. Fuller, J. A. Davis, Geochim. Cosmochim. Acta, 57, 2251 㻔1993㻕.