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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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| 2.
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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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| 3.
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論文
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Begum, Zinnat A. ; Rahman, Ismail M. M. ; Sawai, Hikaru ; Mizutani, Satoshi ; Maki, Teruya ; Hasegawa, Hiroshi
概要:
Development of aminopolycarboxylate chelants (APCs) having enhanced biodegradability is gaining increasing focus to repl
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ace the EDTA and its homologs with those used widely for the ex situ treatment of contaminated soils and are potential eco-threats. The paper reports the chelant-assisted extraction of the toxic metals (Cd, Cu, Pb, and Zn) from the metal-spiked European reference soils (Eurosoil 1 and Eurosoil 4) using biodegradable APCs, namely EDDS, GLDA, and HIDS. The effects of chelant-to-metal molar ratio, solution pH, and metal/chelant stability constants were evaluated, and compared with that of EDTA. The selectivity aptitude of the biodegradable chelants towards the toxic metals was assumed from the speciation calculations, and a proportionate correlation was observed at neutral pH. Pre- and post-extractive solid phase distributions of the target metals were defined using the sequential extraction procedure and dissolution of metals from the theoretically immobilized fraction was witnessed. The effect of competing species (Al, Ca, Fe, Mg, and Mn) concentrations was proven to be minimized with an excess of chelant in solution. The highlight of the outcomes is the superior decontamination ability of GLDA, a biodegradable APC, at minimum chelant concentration in solution and applicability at a wide range of pH environments. © 2012 Springer Science+Business Media Dordrecht.
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| 4.
論文 |
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+, 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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