不同离子液体双水相萃取钯

为实现贵金属钯的绿色、高效萃取,本文使用有“绿色溶剂”之称的离子液体与磷酸钾形成的双水相体系,不加入其它萃取剂对钯(Ⅱ)进行萃取,并采用浊点法对所研究的6种咪唑类离子液体的双结线和系线进行测定。 结果表明,基于氯离子和溴离子的离子液体成相能力和萃取率无显著差异。 阳离子上支链的疏水性是影响咪唑类离子液体成相能力的关键因素之一。 与不含官能团的离子液体相比,支链上嵌入氨基和腈基的离子液体,成相能力较低,但萃取率分别提高了11.57%和34.26%。 当含腈基的离子液体浓度和磷酸钾浓度分别为5.00%和39.55%时,离子液体双水相体系对钯(Ⅱ)的萃取率可达到100%。 本文的研究成果为设计/选择可利用其双水相体系高效萃取钯(Ⅱ)的离子液体提供了理论基础和数据支持。

Palladium(Ⅱ) Extraction Using Different Ionic Liquid-Based Aqueous Biphasic Systems

To establish a green and efficient method to extract the precious metal palladium, we used an aqueous biphasic system(ABS) formed by “green solvent” ionic liquids and potassium phosphate to extract Pd(Ⅱ) without additional extractants. We also determined the binodal curves and tie-lines of 6 imidazolium-based ionic liquids by turbidity point method. The results indicate that there is no significant difference in phase forming ability and extraction rate between chloride-based and bromide-based ionic liquids. The hydrophobicity of the side chain on the cation is one of the key factors affecting phase forming ability of ionic liquids. Compared to ionic liquid without functional groups on the side chain of cation, the introduction of amino group and nitrile group on the side chain reduces the phase forming ability, but increases the extraction rate by 11.57% and 34.26%, respectively. Moreover, the extraction rate by ionic liquid with nitrile group could reach 100% when the concentrations of ionic liquid and potassium phosphate were 5.00% and 39.55%, respectively. The conclusions of this work could provide theoretical basis and data support for the design or choose of ionic liquids for efficient extraction of palladium(Ⅱ) by its aqueous biphasic system.