Neptunium is one of the most important minor actinide elements with some of its isotopes having very long half-lives, therefore necessitating its separation from acidic radioactive wastes. Solvent extraction of Np 4+ and NpO 2 2+ was studied using three multiple diglycolamide (DGA) extractants with n -propyl, n -octyl and 3-pentyl substituents termed as L I , L II and L III , respectively, in a mixed diluent of 5% isodecanol and 95% n -dodecane. For comparison purpose, the extraction of Pu 4+ and UO 2 2+ was carried out under identical conditions. The extraction efficiency of the ligands for the tetravalent ions followed the trend: L II > L I > L III , which changed to L III > L II > L I for the hexavalent ions. While the extraction of the tetravalent ions was reasonably good (ca. 90–98%) with an extremely low (5.0 × 10 −5 M) ligand concentration, poor extraction (ca. 5–16%) of the hexavalent ions was seen even with a 20 times higher concentration of the ligand. In general, Pu 4+ was better extracted than Np 4+ , while NpO 2 2+ was marginally better extracted then UO 2 2+ . A ‘solvation’ type extraction mechanism was proposed based on the extraction profiles obtained as a function of the concentrations of the feed nitric acid, extractant as well as nitrate ion. The extracted species were found out to be M(NO 3 ) 4 ·mL and MO 2 (NO 3 ) 2 ·nL (M = Np or Pu, 1 < m < 2, n ≃ 1).

中文翻译：

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使用二甘醇酰胺官能化杯[4]芳烃从硝酸溶液中萃取四价和六价act离子

是最重要的次act系元素之一，其某些同位素的半衰期非常长，因此必须将其与酸性放射性废物分开。在混合稀释剂中，使用三种分别具有正丙基，正辛基和3-戊基取代基的三种多重二甘醇酰胺（DGA）萃取剂研究了Np 4+和NpO 2 2+的溶剂萃取。含5％异癸醇和95％正十二烷。为了比较目的，在相同条件下进行Pu 4+和UO 2 2+的萃取。四价离子的配体提取效率遵循以下趋势：L II> LI> L III，对于六价离子，其变为L III> L II> LI。虽然四价离子的萃取相当好（约90-98％），但极低（5.％）。当配体浓度为0×10 -5 M时，即使配体浓度高20倍，六价离子的提取率也很低（约5–16％）。通常，Pu 4+的萃取性能优于Np 4+，而NpO 2 2+的萃取性能优于UO 2 2+。根据所获得的萃取曲线，根据进料硝酸，萃取剂以及硝酸根离子的浓度，提出了一种“溶剂化”型萃取机理。发现提取的物质为M（NO 3）4·mL和MO 2（NO 3）2·nL（M = Np或Pu，1 <m <2，n≃1）。根据所获得的萃取曲线，根据进料硝酸，萃取剂以及硝酸根离子的浓度，提出了一种“溶剂化”型萃取机理。发现提取的物质为M（NO 3）4·mL和MO 2（NO 3）2·nL（M = Np或Pu，1 <m <2，n≃1）。根据所获得的萃取曲线，根据进料硝酸，萃取剂以及硝酸根离子的浓度，提出了一种“溶剂化”型萃取机理。发现提取的物质为M（NO 3）4·mL和MO 2（NO 3）2·nL（M = Np或Pu，1 <m <2，n≃1）。