中文摘要：

研究了三辛基氧化膦（TOPO）和三丁基氧化膦（TBPO）在离子液体（ILs）1-烷基-3-甲基咪唑双三氟甲基磺酰亚胺盐（Cnmim NTf2,n=2,4,6,8）中萃取分离UO2（NO3）2.TOPO-C2mim NTf2和TOPO-C4mim NTf2体系萃取UO2（NO3）2时会出现三相,而TBPO萃取UO2（NO3）2的萃合物可以很好地溶解在所有离子液体中.论文也考察了萃取过程中的萃取剂浓度效应、酸效应、盐效应.水相加入HNO3会降低萃取效率.盐效应证明了萃取是一种阳离子交换机理.水相中加入NO3^-能够提高U的萃取,这说明NO3-参与萃取.选择性研究表明：除了在高酸度下对Zr的显著萃取,TBPO-C4mim NTf2萃取体系在低酸度下对U呈现较好的选择性;去除U后,在低酸度下该体系对三价Nd仍保持较好的选择性.通过定量比较离子液体中NO3-进入量,电喷雾质谱（ESI-MS）和紫外光谱表征确定了TBPO-Cnmim NTf2中萃取机理的差异性.萃取中存在两种萃合物,即UO2（TBPO）3（NO3）^＋和UO2（TBPO）3^2＋,其中UO2（TBPO）3（NO3）^＋的比例从C2mim NTf2体系到C8mim NTf2体系逐渐增加.

英文摘要：

The extraction of UO2（NO3）2from aqueous solution was investigated using trioctylphosphine oxide（TOPO） and tributylphosphine oxide（TBPO） in ionic liquids（ILs）（Cnmim NTf2, n=2, 4, 6, 8）. A third phase was formed in the TOPO-C2 mim NTf2and TOPO-C4 mim NTf2extraction systems, whereas the extracted species of TBPO-Cnmim NTf2（n=2, 4, 6, 8） were well soluble in all ILs. The influence of the concentrations of the extractant,nitric acid, and salt on the extraction efficiency was also investigated. Adding HNO3 to the aqueous phase decreased the extraction efficiency. The effect of salt indicates the presence of a cation-exchange mechanism in the extraction. The addition of NO3^- in the aqueous phase increased the extraction efficiency of U, which indicates that NO3-participates in the extraction. Selective extraction research indicates that TBPO-C4 mim NTf2exhibits good selectivity for U at low acid concentration despite the significant extraction efficiency on Zr at high acid concentration. After removing U, TBPO-C4 mim NTf2still showed high selectivity for Nd at low acid concentration. We also confirmed the difference of the extraction mechanisms among TBPO-Cnmim NTf2 by quantitative measurement of NNO3-in ILs, electrospray ionization mass spectroscopy（ESI- MS）, and UV spectroscopy. There are two extraction species（UO2（TBPO）3（NO3）^＋and UO2（TBPO）3^2＋） and the proportion of UO2（TBPO）3（NO3）^＋increases from C2 mim NTf2to C8 mim NTf2.