Extraction of Th(IV) from an HNO3 Solution by Diglycolamide in Ionic Liquids

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• 作者：Yinglin Shen ; Shaofei Wang ; Lun Zhu ; Jianjun Wang ; Wangsuo Wu
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2011
• 出版时间：December 21, 2011
• 年：2011
• 卷：50
• 期：24
• 页码：13990-13996
• 全文大小：864K
• 年卷期：v.50,no.24(December 21, 2011)
• ISSN：1520-5045

文摘

Extraction of thorium(IV) from a nitric acid solution into various 1-alkyl-3-methylimidazolium hexafluorophosphate ([C_nmim][PF₆], n = 4,6,8) ionic liquids (ILs) was investigated using N,N,N鈥?N鈥?tetrabutyl-3-oxapentanediamide (TBDA) and N,N鈥?dimethyl-N,N鈥?dibutyl-3-oxapentanediamide (MBDA) as the extractants. The extraction efficiency of Th⁴⁺ ions in the ionic liquid is higher than that obtained in chloroform under low nitric acid concentration. The extraction mechanism has been studied by slope analysis, UV鈥搗is measurement, and extraction tests. The conventional log鈥搇og plot analysis of the extraction equilibrium data reveals that Th⁴⁺ ions are extracted as cation complexes characterized by a metal/ligand ratio of 1:2 using MBDA as an extractant. In addition Th⁴⁺ ions form 1:2 complexes with TBDA in [bmim]PF₆ and [hmim]PF₆ and 1:1 complexes in [omim][PF₆] and chloroform. The mode of partitioning of thorium ions into [bmim]PF₆ and [hmim]PF₆ with TBDA appears to proceed predominantly via a cation-exchange mechanism, whereas for [omim][PF₆] thorium extraction mechanism is changed from an cation-exchange process to one involving extraction of a neutral thorium-TBDA-nitrato complex as the aqueous nitrate concentration is increased.