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| 1.
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論文
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Yamamoto, Masayoshi ; Sakanoue, Masanobu ; 山本, 政儀 ; 阪上, 正信
概要:
金沢大学環日本海域環境研究センター<br />Laboratory experiments using radiotracer of americium (241Am) and humic acid isolated from natura
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l surface soil have been conducted to evaluate the effect of added humic acid on the behavior of Am(III) in aqueous solution and the stability constant of the complex formed between Am(III) and humic acid. The former experiments were performed in the synthetic aqueous medium containing Ca or in fresh rain water at pH 6.5 and 4.5. At pH 6.5 in the absence of humic acid, Am(III) in both solutions [(Ca: 10 ppm) or rain water] was almostly adsorbed on the wall of the polyethylene vial used, and the major fraction of Am left in the solution was retained on the filter of 0.45μm pore size. On the other hand, in the presence of humic acid (100 ppm), the adsorption of Am on the vail was not observed, and the decrease of the retention of Am on the same filter suggests its complex formation with humic acid. At pH 4.5, the behavior of Am(III) in the solution (Ca: 10 ppm) was not influenced by the addition of humic acid (100 ppm). When the quantities of Ca were increased in the solution at a constant amount of humic acid, insoluble complexes were formed according to the increase of Ca to humic acid, and Am was scavenged over 90% as the insoluble complexes. The study of stability constant indicated that Am(III) had the strong interaction with humic acid.
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| 2.
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論文
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Yamamoto, Masayoshi ; Sakanoue, Masanobu ; 山本, 政儀 ; 阪上, 正信
概要:
金沢大学環日本海域環境研究センター<br />Laboratory experiments using radiotracer of americium (241Am) and humic acid isolated from natura
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l surface soil have been conducted to evaluate the effect of added humic acid on the behavior of Am(III) in aqueous solution and the stability constant of the complex formed between Am(III) and humic acid. The former experiments were performed in the synthetic aqueous medium containing Ca or in fresh rain water at pH 6.5 and 4.5. At pH 6.5 in the absence of humic acid, Am(III) in both solutions [(Ca: 10 ppm) or rain water] was almostly adsorbed on the wall of the polyethylene vial used, and the major fraction of Am left in the solution was retained on the filter of 0.45μm pore size. On the other hand, in the presence of humic acid (100 ppm), the adsorption of Am on the vail was not observed, and the decrease of the retention of Am on the same filter suggests its complex formation with humic acid. At pH 4.5, the behavior of Am(III) in the solution (Ca: 10 ppm) was not influenced by the addition of humic acid (100 ppm). When the quantities of Ca were increased in the solution at a constant amount of humic acid, insoluble complexes were formed according to the increase of Ca to humic acid, and Am was scavenged over 90% as the insoluble complexes. The study of stability constant indicated that Am(III) had the strong interaction with humic acid.
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| 3.
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論文
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Begun, Zinnat A. ; Rahman, Ismail M.M. ; Hasegawa, Hiroshi ; 長谷川, 浩
概要:
金沢大学理工研究域物質化学系<br />The complexation of SrII and geochemically-related elements (MgII, CaII, BaII, and YIII) with biodeg
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radable aminopolycarboxylate chelators (DL-2-(2-carboxymethyl)nitrilotriacetic acid (GLDA) and 3-hydroxy-2,2′-iminodisuccinic acid (HIDS)) was evaluated with the objective of using in the chemical-induced washing remediation of radioactive solid waste. The stability constants (log10KML) for metal-chelator (ML) complexes between M (MgII, CaII, SrII, BaII, or YIII) and L (GLDA or HIDS) in the aqueous matrix was derived from experimental potentiometric data (M:L = 1:1; ionic strength, I = 0.10 mol·dm− 3; T = 25 ± 0.1 °C). The formation of ML2 − species was dominant in the systems with MgII, CaII, SrII, or BaII, while M(OH)L2 − or M(OH)2L3 − was the major species with YIII. The stability of YIII-L complexes was higher than that of MgII, CaII, SrII, or BaII, while the order for complexation strength of GLDA and HIDS was not similar with divalent ions: M-GLDA (log10KMg-L < log10KCa-L > log10KSr-L > log10KBa-L), M-HIDS (log10KMg-L > log10KCa-L > log10KSr-L > log10KBa-L). The conditional stability constants for the ML systems was also derived in terms of pH (2 to 12), and compared with that of EDTA and EDDS. The data trend indicated that the overall stability of the complexes of MgII, CaII, SrII, BaII, or YIII with GLDA or HIDS was better than the biodegradable chelator EDDS, which was frequently recommended as the alternative to EDTA. © 2017 Elsevier B.V.<br />Embargo Period 12 months
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| 4.
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論文
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Begum, Zinnat A. ; Rahman, Ismail M. M. ; Tate, Yousuke ; Egawa, Yuji ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
The protonation and complex formation equilibria of two biodegradable aminopolycarboxylate chelants {dl-2-(2-carboxymeth
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yl)nitrilotriacetic acid (GLDA) and 3-hydroxy-2,2′-iminodisuccinic acid (HIDS)} with Ni 2+, Cu 2+, Zn 2+, Cd 2+ and Pb 2+ ions were investigated using the potentiometric method at a constant ionic strength of I = 0.10 mol·dm -3 (KCl) in aqueous solutions at 25 ± 0.1 °C. The stability constants of the proton-chelant and metal-chelant species for each metal ion were determined, and the concentration distributions of various complex species in solution were evaluated for each ion. The stability constants (log 10K ML) of the complexes containing Ni 2+, Cu 2+, Zn 2+, Cd 2+ and Pb 2+ ions followed the identical order of log 10K CuL > log 10K NiL > log 10K PbL > log 10K ZnL > log 10K CdL for either GLDA (13.03 > 12.74 > 11.60 > 11.52 > 10.31) or HIDS (12.63 > 11.30 > 10.21 > 9.76 > 7.58). In each case, the constants obtained for metal-GLDA complexes were larger than the corresponding constants for metal-HIDS complexes. The conditional stability constants (log 10 {Mathematical expression}) of the metal-chelant complexes containing GLDA and HIDS were calculated in terms of pH, and compared with the stability constants for EDTA and other biodegradable chelants. © 2012 Springer Science+Business Media New York.
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| 5.
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論文
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Begum, Zinnat A. ; Rahman, Ismail M. M. ; Tate, Yousuke ; Egawa, Yuji ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
The protonation and complex formation equilibria of two biodegradable aminopolycarboxylate chelants {dl-2-(2-carboxymeth
…
yl)nitrilotriacetic acid (GLDA) and 3-hydroxy-2,2′-iminodisuccinic acid (HIDS)} with Ni 2+, Cu2+, Zn2+, Cd2+ and Pb 2+ ions were investigated using the potentiometric method at a constant ionic strength of I = 0.10 mol·dm-3 (KCl) in aqueous solutions at 25 ± 0.1 C. The stability constants of the proton-chelant and metal-chelant species for each metal ion were determined, and the concentration distributions of various complex species in solution were evaluated for each ion. The stability constants (log10 K ML) of the complexes containing Ni2+, Cu2+, Zn2+, Cd2+ and Pb2+ ions followed the identical order of log10 K CuL > log10 K NiL > log10 K PbL > log10 K ZnL > log10 K CdL for either GLDA (13.03 > 12.74 > 11.60 > 11.52 > 10.31) or HIDS (12.63 > 11.30 > 10.21 > 9.76 > 7.58). In each case, the constants obtained for metal-GLDA complexes were larger than the corresponding constants for metal-HIDS complexes. The conditional stability constants (log10 $$ K-{\text{ML}}^{'} $$) of the metal-chelant complexes containing GLDA and HIDS were calculated in terms of pH, and compared with the stability constants for EDTA and other biodegradable chelants. © 2012 Springer Science+Business Media New York.
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