1,2,3-三唑类萃取剂对硝酸溶液中钯（Ⅱ）的萃取研究

发布时间：2018-08-05 20:22

【摘要】：本论文合成了一类新型的1,2,3-三唑(1,2,3-Tz)类配体,该类配体难溶于水,可溶于氯仿等传统有机溶剂以及咪唑类离子液体。1,2,3-三唑类化合物富含给电子的氮原子,易与具有软酸性质的钯(II)形成稳定的配合物,我们将该类化合物用于钯的萃取研究。分别研究了接触时间、萃取剂结构和浓度、水相酸度、硝酸根离子(NO3-)浓度对萃取Pd~(2+)的影响。我们选择了两种性能较好的1,2,3-三唑类萃取剂Tz1和Tz2,研究其在离子液和氯仿中萃取Pd~(2+)的情况,结果表明该萃取过程能较快的达到萃取平衡,该类萃取剂在离子液中的萃取能力强于在氯仿中,溶液酸性越强,萃取效果越好。并对这两种萃取剂在离子液和氯仿中萃取Pd~(2+)的机理做了详细的研究,通过斜率法和摩尔比法,推测1,2,3-三唑类萃取剂在离子液和氯仿中与Pd~(2+)主要形成1:1的萃合物;利用傅里叶变换红外光谱分析法(FTIR)和电喷雾质谱分析法(ESI-MS)对萃取Pd~(2+)形成的萃合物进行了表征,推测出1,2,3-三唑类萃取剂是通过三唑环的氮原子和吡啶环上的氮原子与Pd~(2+)配位;在离子液中主要通过中性溶剂化作用萃取Pd~(2+),水相酸度较高时还存在少量的阴离子交换作用,而在氯仿中的萃取过程仅存在中性溶剂化作用。此外,我们对这两种配体萃取Pd~(2+)的选择性做了研究,结果表明1,2,3-三唑类萃取剂在离子液中可以将Pd~(2+)从含多种金属离子的混合溶液中分离出来,而对混合溶液中的其它金属离子,如碱金属、碱土金属、镧系、锕系等元素的金属离子基本没有萃取。我们还对反萃体系做了研究,结果表明较低酸度的硝酸溶液和低酸度酸化的硫脲溶液都可以把Pd~(2+)从离子液中反萃出来。我们对两种萃取剂在离子液中萃取Pd~(2+)的热力学也做了探讨,通过实验和计算得到了该萃取反应的热力学参数(ΔH,ΔS和ΔG),结果说明1,2,3-三唑类萃取剂对Pd~(2+)的萃取过程是一个吸热的自发萃取过程。
[Abstract]:A new class of 1,2,3- three azole (1,2,3-Tz) ligands, which are difficult to dissolve in water, can be dissolved in the traditional organic solvents such as chloroform, and the imidazole ionic liquid.1,2,3- three azole compounds are rich in electron nitrogen atoms. It is easy to form a stable complex with palladium (II) with the properties of soft acid. We use this compound to be used in palladium. The effects of contact time, structure and concentration of extractants, water phase acidity and nitrate ion (NO3-) concentration on the extraction of Pd~ (2+) were studied. Two kinds of 1,2,3- three azole extractants, Tz1 and Tz2, were selected to study the extraction of Pd~ (2+) in ionic liquid and chloroform. The results showed that the extraction process could be faster. The extraction ability of this kind of extractant in ionic liquid is stronger than in chloroform. The better the solution is, the better the extraction effect is. The mechanism of the extraction of Pd~ (2+) in the ionic liquid and the chloroform of these two extractants is studied in detail. By the slope method and the molar ratio method, it is speculated that the 1,2,3- three azole extractants are in the ionic liquid and chloroform. Pd~ (2+) is mainly formed with Pd~ (2+), the extraction of Pd~ (2+) is characterized by Fourier transform infrared spectroscopy (FTIR) and electrospray ionization mass spectrometry (ESI-MS). It is conjectured that the 1,2,3- three azole extractant is the nitrogen atom of the three azole ring and the nitrogen atom of the pyridine ring with the Pd~ (2+) coordination; and in the ionic liquid. In order to extract Pd~ (2+) by neutral solvation, there is a small amount of anion exchange when the acidity of the aqueous phase is high, and the extraction process in chloroform only has neutral solvation. In addition, we have studied the selectivity of these two ligands for the extraction of Pd~ (2+). The results show that the 1,2,3- three azole extractants can make Pd~ in the ionic liquid. 2+) separates from a mixed solution containing a variety of metal ions, and the metal ions of other metal ions in the mixed solution, such as alkali metal, alkaline earth metal, lanthanide, actinide, etc., are basically not extracted. We have also studied the stripping system. The results show that the low acid nitrate solution and the low acidity acidified thiourea solution are all available. The Pd~ (2+) is extracted from the ionic liquid. The thermodynamics of the extraction of Pd~ (2+) in the ionic liquid of the two extractants is also discussed. The thermodynamic parameters (delta H, Delta S and delta G) of the extraction reaction are obtained by experiments and calculations. The results show that the extraction process of 1,2,3- three azolics is a spontaneous extraction process of the endothermic process.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O658.2;O614.823

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