Scientific Basis for Efficient Extraction of Uranium from Seawater. I: Understanding the Chemical Speciation of Uranium under Seawater Conditions
Scientific Basis for Efficient Extraction of Uranium from Seawater. I: Understanding the Chemical Speciation of Uranium under Seawater Conditions
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DOI：
10.1021/acs.iecr.5b03679
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发表时间：
2016-04-20
影响因子：
4.2
通讯作者：
Rao, Linfeng
中科院分区：
文献类型：
--
作者：
Endrizzi, Francesco;Leggett, Christina J.;Rao, Linfeng
近年来，由于全世界对核燃料的需求不断增加，并由于努力寻找陆地铀矿开采的可持续替代办法，从海水中回收铀的前景已成为一个令人感兴趣的话题。迄今为止，从海水中提取和浓缩铀的最先进和最有前途的方法是使用含有偕胺肟结合部分的聚合物吸附剂。在研究的许多不同的部分中，戊二酰亚胺-二肟是最有前途的一个，即使在碳酸盐的存在下也能与U（VI）形成非常稳定的络合物。为了正确评估铀对偕胺肟底物的亲和力，需要全面了解铀的水化学平衡。本文综述了铀在海水中的化学平衡，着重讨论了形成稳定配合物M-m（UO_2）（CO_3）（3）（（2 m-4））（aq）（M = Ca或Mg，m = 0-2）的溶液平衡。这些二元和三元物种在海水中的铀化学中占主导地位，最近已成为文献中几篇论文的研究对象。本文研究了导致已知矿物形成的UO_（22+）在海水中的溶解度平衡，这些矿物包括钙钛矿、Ca-2（UO_2）（CO_3）（3）中心点10 H（2）O（cr）、硅锌矿、CaMg（UO_2）（CO_3）（3）中心点12 H（2）O（cr）、贝氏矿Mg-2（UO_2）（CO_3）（3）中心点18 H（2）O（cr）和钙铝石。Na_2Ca（UO_2）（CO_3）（3）中心点6 H_（2）O（Cr）等。这些固体化合物的溶度积（log K-s（0））的新计算值的基础上，目前提出的形态模型，其中包括最新的上述数据的水相形态的UO 22+。基于这些数据，模拟形态图计算，无论是在零离子强度和海水介质。结合铀与戊二酰亚胺二肟的形态数据，这些模型提供了一个更好的，更全面的图片的U（VI）在海水中的化学平衡，同时也提供了有用的工具，以帮助评估其回收的可行性，通过偕胺肟为基础的收集系统。
In recent years, the prospective recovery of uranium from seawater has become a topic of interest owing to the increasing demand for nuclear fuel worldwide and because of efforts to find sustainable alternatives to terrestrial mining for uranium. To date, the most advanced and promising method of extracting and concentrating uranium from seawater involves the use of polymeric sorbents containing the amidoxime binding moiety. Among a number of different moieties investigated, glutaroimide-dioxime is the most promising one, forming very stable complexes with U(VI) even in the presence of carbonate. To properly assess the affinity of uranium toward the amidoxime substrates, a comprehensive knowledge of the aqueous chemical equilibria of uranium is required. With this aim, in this paper we review the chemical equilibria of uranium (as UO22+) in seawater, focusing on the solution equilibria leading to the formation of the stable complexes, M-m(UO2)(CO3)(3)((2m-4)) (aq) (M = Ca or Mg, m = 0-2). These binary and ternary species dominate the chemistry of uranium in seawater and have recently been the object of study in several papers in the literature. The solubility equilibria of UO22+ in seawater leading to the formation of the known minerals, including Liebigite, Ca-2(UO2)(CO3)(3)center dot 10H(2)O(cr), Swartzite, CaMg(UO2)(CO3)(3)center dot 12H(2)O(cr), Bayleyite Mg-2(UO2)(CO3)(3)center dot 18H(2)O(cr), and Andersonite, Na2Ca(UO2)(CO3)(3)center dot 6H(2)O(cr), are also critically reviewed. Newly calculated values of the solubility products (log K-s(0)) for these solid compounds are presented based on the currently proposed speciation model that includes the most recent aforementioned data for the aqueous speciation of UO22+. Based on these data, simulated speciation diagrams are calculated, both at zero ionic strength and in seawater-like media. In combination with the speciation data for uranium with glutaroimide-dioxime, these models provide a better, more comprehensive picture of the chemical equilibria of U(VI) in seawater while also providing useful tools to help assess the feasibility of its recovery through amidoxime-based collection systems.