Effect of DTPA on the Extractions of Actinides(III) and Lanthanides(III) from Nitrate Solution into Todga/n‐Dodecane
Effect of DTPA on the Extractions of Actinides(III) and Lanthanides(III) from Nitrate Solution into Todga/n‐Dodecane
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DOI：
10.1081/sei-200037727
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发表时间：
2004-12
影响因子：
2
通讯作者：
A. Apichaibukol;Y. Sasaki;Y. Morita
中科院分区：
文献类型：
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作者：
A. Apichaibukol;Y. Sasaki;Y. Morita
摘要为了分离三价镧系元素[Ln（III）]和锕系元素[An（III）]，采用二乙烯三胺-N，N，N′，N″，N″-五乙酸（DTPA）螯合剂，选择性地降低Au（III）在TODGA/正十二烷和硝酸盐溶液中的分配比（D）。An（III）和Ln（III）的D值随着水相pH的增加而减小。它们对轻Ln（III）的依赖性不同于对中重Ln（III）的依赖性，这意味着DTPA 5 −与Ln（III）的络合能力彼此不同。使用H5 DTPA的解离常数和Ln-DTPA的形成常数进行D值的计算。结果表明，在萃取反应的中间阶段，Ln（III）离子不发生络合作用，并证明了在Ln-TODGA-DTPA萃取体系中D与pH的曲线关系。镅（III）和Cm（III）与DTPA 5-形成更稳定的1：1络合物，并且显示出比轻Ln（III）更低的D值，预计对轻Ln（III）具有高分离度。测定的分离因子（SF）、D Ln/D Am和D Ln/D Cm在1-60范围内变化。
Abstract For the separation of trivalent lanthanides [Ln(III)] and actinides[An(III)], the chelating agent, diethylenetriamine‐N,N,N′,N″,N″‐pentaacetic acid (DTPA), was used to decrease selectively the distribution ratios (D) of An(III) between TODGA/n‐dodecane and nitrate solution. The D values of An(III) and Ln(III) decrease with an increase of the pH of the aqueous phase. Their dependencies for light Ln(III) are different from those for medium and heavy Ln(III), which implies that the complexing ability of DTPA5− with Ln(III) is different from each other. The calculation of D values was performed using dissociation constants of H5DTPA and the formation constants of Ln–DTPA. Their results suggested the existence of Ln(III) ions without any complexation at the intermediate stage of the extraction reactions and demonstrated the curvilineal relation of D with pH in Ln–TODGA–DTPA extraction system. Americium(III) and Cm(III) form more stable 1:1 complex with DTPA5− and show lower D values than light Ln(III), it is expected to have a high separation against light Ln(III). The separation factors (SF), D Ln/D Am, and D Ln/D Cm, determined varied within the range of 1–60.