Extraction of Actinides with Different 6,6′‐Bis(5,6‐Dialkyl‐[1,2,4]‐Triazin‐3‐yl)‐[2,2′]‐Bipyridines (BTBPs)

Abstract

The extraction of Am(III), Th(IV), Np(V), and U(VI) from nitric acid by 6,6′‐bis(5,6‐dialkyl‐[1,2,4]‐triazin‐3‐yl)‐[2,2′]‐bipyridines (C2‐, C4‐, C5‐, and CyMe₄‐BTBP) was studied. Since only americium and neptunium extraction was dependent on the BTBP concentration, computational chemistry was used to explain this behavior. It has been shown that the coordination of the metal played an important role in forming an extractable complex into the organic phase, thus making it possible to extract pentavalent and trivalent elements from tetravalent and hexavalent elements. This is very important, especially because it shows other possible utilizations of a group of molecules meant to separate the actinides from the lanthanides. In addition, the level of extraction at very low or no BTBP concentration was explained by coordination chemistry.     

The peculiarities of formation of the metal nanoparticles in irradiated polymer metal complexes

The radiation-induced reduction of metal ions in the films of triple metal polymer complexes of polyacrylic acid-polyethyleneimine-copper(II) or nickel(II) (PAA-PEI-Cu²⁺ or PAA-PEI-Ni²⁺) was studied by EPR and transmission electron microscopy (TEM). It was shown that irradiation of the swollen polymer films in the water-alcohol environment resulted in effective reduction of the metal ions. The exchange between the swollen film and outer environment was found to be an important factor for ion reduction and stabilization of metal particles. EPR data have revealed pronounced effect of the ligand environment on the reduction efficiency. The electron microscopy studies have demonstrated that the dimensions of main fraction of metal particles obtained by the radiation-chemical reduction are in the range of 2-2.5 nm both for Cu and for Ni complexes.     

从~(237)Np中分离高纯度的~(233)Pa的新方法

一、引言~(231)Pa是AcU(~(235)U)天然放射系的一个重要成员。在海洋地球化学和地质年代学研究中,它是一个非常重要的核素。但可作为~(231)Pa分离用的产额示踪剂的核素只有~(233)Pa,它是β-γ发射体,半衰期短(27.0 d)。因此如果能够简便地制得示踪剂~(233)Pa,对~(231)Pa年代学的研究和应用以及对镤化学和放射化学的研究无疑是个促进。     

大量~(238)Pu中微量~(237)Np的测定

一、绪言关于镎的分析方法,国内外都进行了大量的工作,报道的文献也很多[1—3],而经常采用的有:(1)放化测量法,这是最常用的一种方法,尽管~(237)Np的比放比较低(1.56×10~3衰变/μg·min),但计数法还是比化学法,化学光谱法灵敏。(2)分光光度法,此法虽然比放化测量灵敏度稍低,但是在含镎的样品中,往往总是伴随有其它α放射性元素,而这些杂质元素比放经常比镎要强得多,因此采用α计数法测量镎时,对其它杂质要求有很     

Supposed existence of Np4+ in a genuine dissolver solution from the results of extraction simulation by PARC-L code

With a genuine spent fuel solution (a dissolver solution), a laboratory-scale reprocessing experiment of an extraction–separation process was performed using mixer-settlers as extractors. In the experiment, n-butyraldehyde was utilized as a reducing reagent of Np^(VI)O₂²⁺ to Np^(V)O₂⁺ for the purpose to distinguish Np^(VI)O₂²⁺ from Np⁴⁺. From the Np concentration in the aqueous phase, Np would be extracted from the dissolver solution together with U and Pu. The scrutiny of Np behavior was performed utilizing 66 cases of calculation results by a Japan Atomic Energy Agency open extraction simulation code, the Program for Advanced Extraction with Radiation Effect Calculation–Lightened version. From the scrutiny, the authors found that the calculation result with 60% of Np⁴⁺ in the dissolver solution represented the best experimental extraction–separation behavior of Np. Therefore, it was supposed that the dissolver solution contained sufficient proportion of Np⁴⁺ to affect the extraction–separation behavior of Np.     

237Np在几种实验用材料上的器壁吸附研究

描述了^237Np在不同材质（聚四氟乙烯、聚氯乙烯、聚丙烯、玻璃、有机玻璃和尼龙）上和不同实验条件（pH＝2无土,pH＝9有土、无土）下的吸附情况。实验结果表明：所选的材料在低pH值无土和高pH值有土的情况下对^237Np的吸附有很弱的,高pH值无土的情况下吸附较强。     

Np，Pu在地下水和工程屏障平衡水中的形态计算研究

采用EQ3／6地球化学模式和计算方法研究了放射性废物处置中Np和Pu在地下水和工程屏障平衡水中的化学形态,计算分析了温度、浓度、pH值、Eh值、CO2等对上述2个元素形态的影响。结果表明,地下水中Np的形态主要有4种：NpO2^ ,NpO2CO3^-,NpO2OH和Np(OH)5^-,当CO3^2-质量浓度高时,Np主要以NpO2(CO3)2^3-存在。pH值以Np形态的影响主要表面在上述4种形态分布的相对比例及OH^-与CO3^2-的竞争配合作用。Eh值低于0．2V时,Np主要为四价;0．2－0．7V时,五价为主;大于0．7V时,出现六价。Pu的形态主要为Pu(OH)5^-。CO3^2-的质量浓度对四价钚的形态分布不产生影响,但CO3^2-却与Pu（Ⅵ）有很强的配合能力。Eh值低于－0．5V时,Pu主要为三价;－0．4－0．6V,五价为主;大于0．7V时,六价为主。     

237Np在黄土和石英砂中迁移的影响因素

通过静态实验和动态实验,研究了放射性溶液活度、液-固比、pH值、碳酸盐、离子强度和黄土粒度等对超铀核素^237Np在黄土中的吸附分配系数的影响,以及有机质HA对^237Np在石英砂柱中迁移的影响。     

电沉积法制备镅、钚和镎的α源

以０．１ｍｏｌ／Ｌ硫酸铵为电沉积液,在铁阳极与不锈钢阴极之间施加约１５Ｖ直流电压,控制电流密度为０．６５Ａ／ｃｍ＾２,沉积４０ｍｉｎ,镅、钚和镎可以定量地沉积在阴极上,其收率均≥９８％。探讨了１８种有代表性的共存物对电沉积率的影响,结果表明,多数阳离子（碱金属、碱土金属除外）影响电沉积率或分辨率;少量ＮＯ＾－３、Ｃｌ＾－、磷酸三丁酯（ＴＢＰ）、三烷基氧（ＴＲＰＯ）、煤油或草酸不影响沉积结果。当电解