Scientific Basis for Efficient Extraction of Uranium from Seawater. I: Understanding the Chemical Speciation of Uranium under Seawater Conditions

作者：Francesco Endrizzi, Christina J. Leggett, Linfeng Rao · 发表于：Industrial & Engineering Chemistry Research · 年份：2016 · DOI：10.1021/acs.iecr.5b03679 · 被引用次数：204 · 研究领域：Radioactive element chemistry and processing、Radioactive contamination and transfer、Extraction and Separation Processes

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 UO 2 2+ ) in seawater, focusing on the solution equilibria leading to the formation of the stable complexes, M m (UO 2 )(CO 3 ) 3 (2 m –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 UO 2 2+ in seawater leading to the formation of the known minerals, including Liebigite, Ca 2 (UO 2 )(CO 3 ) 3 ·10H 2 O(cr), Swartzite, CaMg(UO 2 )(CO 3 ) 3 ·12H 2 O(cr), Bayleyite Mg 2 (UO 2 )(CO 3 ) 3 ·18H 2 O(cr), and Andersonite, Na 2 Ca(UO 2 )(CO 3 ) 3 ·6H 2 O(cr), are also critically reviewed....