Application of Hydrofluoroethers as Diluent to Solvent Extraction of Zinc(II) Using Phosphorus Acid Extractants
Application of Hydrofluoroethers as Diluent to Solvent Extraction of Zinc(II) Using Phosphorus Acid Extractants
复制标题
氢氟醚作为稀释剂在磷酸萃取剂溶剂萃取锌(II)中的应用
DOI：
10.1252/jcej.38.94
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发表时间：
2005
影响因子：
0.8
通讯作者：
Katsuroku Takahashi
中科院分区：
文献类型：
--
作者：
T. Kinoshita;S. Akita;S. Nii;F. Kawaizumi;Katsuroku Takahashi
在锌(II)的溶剂萃取法中，氢氟醚被用作磷酸萃取剂的稀释剂。由于它们的不燃性、化学稳定性和无毒性，它们是传统有机稀释剂的有前途的替代品。本研究中使用的氢氟醚是乙基全氟丁醚和乙基全氟异丁醚的混合物以及甲基全氟丁醚和甲基全氟异丁醚的混合物(HFE-7100)。在所考察的萃取剂中，二(2-乙基己基)磷酸(D2EHPA)和2-乙基己基磷酸单-2-乙基己基酯(EHPNA)两种磷酸萃取剂均可溶于两种氢氟醚。由于氢氟醚的比重高，在水中的溶解度低，相分离速度快，产物物相清晰。在磷酸体系中，D2EHPA体系的萃取率高于EHPNA体系，但两种氢氟醚的萃取行为差别不大。考察了平衡溶液pH和萃取剂浓度对锌萃取率的影响，提出了锌萃取率的计量关系式。锌(II)的萃取平衡常数高于氯仿和四氯化碳等常规氯化有机溶剂。用稀酸溶液成功地实现了锌(II)的反萃取，并对几种重金属进行了分离。此外，萃取剂和氢氟醚在水相中的洗脱率很低，这使得本体系更具吸引力。
Hydrofluoroethers have been applied as diluent for phosphorus acid extractants in the solvent extraction of zinc(II). They are promising alternatives to conventional organic diluents because of their non-flammability, chemical stability and non-toxicity. Hydrofluoroethers used in this study are a mixture of ethylperfluorobutylether and ethylperfluoroisobutylether and a mixture of methylperfluorobutylether and methylperfluoroisobutylether (HFE-7100). Among the extractants examined, two phosphorus acid extractants, di-(2-ethylhexyl)phosphoric acid (D2EHPA) and 2-ehtylhexyl phosphoric acid mono-2-ethylhexyl ester (EHPNA) were soluble in both hydrofluoroethers. Because of the high specific gravity of hydrofluoroethers and their low solubility in water, phase-separation was rapid and the resulting phases were clear. In the extraction of zinc(II) using the phosphorus acids, the system with D2EHPA gave higher extraction than that with EHPNA, while there was little difference in the extraction behavior between the two hydrofluoroethers. The effects of the equilibrium solution pH and the extractant concentration on the zinc extraction were examined, and the stoichiometric relationship for the extraction was proposed. The extraction equilibrium constants for zinc(II) were found to be higher than those with conventional chlorinated organic solvents such as chloroform and carbon tetrachloride. The backward extraction of zinc(II) was satisfactorily attained with a dilute acid solution, and the separation of several heavy metals was also demonstrated. Moreover, the elution of the extractants and hydrofluoroethers into the aqueous phase was very low, and this makes the present system more attractive.