Coordination extraction for separating vanadium and impurities from black shale HCl leachate at low pH using D2EHPA and EHEHPA mixture
Coordination extraction for separating vanadium and impurities from black shale HCl leachate at low pH using D2EHPA and EHEHPA mixture
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DOI：
10.1016/j.seppur.2022.122088
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发表时间：
2022-09
影响因子：
8.6
通讯作者：
Hong Liu;Yi-min Zhang;Jing Huang;Tao Liu;Yi-ping Wang
中科院分区：
文献类型：
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作者：
Hong Liu;Yi-min Zhang;Jing Huang;Tao Liu;Yi-ping Wang
全面研究钒离子与萃取剂的配位行为对建立新型高效萃取体系具有重要指导意义。本文研究了D2 EHPA和EHEHPA作为组合萃取剂分离钒和杂质离子的协同效应及其机理。最佳萃取条件为：D2 EHPA：EHEHPA = 7：3，料液pH = 1.4，萃取剂浓度20%，搅拌时间8 min，相比（O/A）= 1：2。在此条件下，钒、铁、铝和锌的提取率分别为79.22%、16.6%、2.61%和4.29%。在三级萃取、两级反萃的最佳工艺条件下，经氨沉后可得到纯度为98.62%的V2 O 5产品。FTIR和ESI-MS分析结果表明，D2 EHPA和EHEHPA在氢键作用下形成HA·HB二聚体，该二聚体具有优良的萃取性能和选择性。溶液化学和量子化学结果表明，萃取界面氯离子与VO 2+之间的配位键发生了解离，但只有VO 2+离子进入有机相与萃取剂反应，最终萃取剂以VOA 2·HB的形式存在。
Comprehensive study on the coordination behavior of vanadium ions and extractants is an important guide to the establishment of new efficient extraction systems. In this study, the synergistic effect and mechanism of D2EHPA and EHEHPA as combined extractants for separating vanadium and impurity ions were investigated in detail. The optimal extraction conditions were D2EHPA:EHEHPA ratio 7:3, feed solution pH 1.4, extractant concentration 20%, stirring time 8 min, and phase ratio (O/A) 1:2. Under these optimal conditions, the extraction percentages of V, Fe, Al, and Zn were 79.22%, 16.6%, 2.61%, and 4.29%, respectively. Under the optimal conditions of three-stage extraction and two-stage stripping, V2O5product with 98.62% purity could be obtained after ammonia precipitation. FTIR spectroscopy and ESI-MS analysis results indicated that D2EHPA and EHEHPA could form HA·HB dimer under the action of hydrogen bonding, and this dimer exhibited excellent extraction performance and selectivity. The solution chemistry and quantum chemistry results showed the dissociation process of the coordination bond between chloride ions and VO2+at the extraction interface; however, only VO2+ions entered the organic phase to react with the extractant, and the final extractant appeared as VOA2·HB.