Tachibana Yu, Kalak Tomasz, Tanaka Masahiro
Department of Nuclear System Safety Engineering, Graduate School of Engineering, Nagaoka University of Technology, 1603-1, Kamitomioka-machi, Nagaoka-shi, Niigata 940-2188, Japan.
Department of Industrial Products and Packaging Quality, Institute of Quality Science, Poznań University of Economics and Business, Niepodległości 10, Poznań 61-875, Republic of Poland.
ACS Omega. 2022 Jul 27;7(31):27410-27421. doi: 10.1021/acsomega.2c02427. eCollection 2022 Aug 9.
The use of the composite adsorbents composed of benzo-15-crown-5 (abbreviated as BC15) and benzo-18-crown-6 (BC18) for the simultaneous recovery of vanadium (V), uranium (U), and lithium (Li) from seawater has been proposed for industrial applications. The adsorption and desorption behavior of these elements on BC15 and BC18 has been examined in various types of aqueous solutions over a wide temperature range. As a result, it was shown that BC15 and BC18 have sufficient adsorption ability for the simultaneous recovery of V, U, and Li from seawater. Moreover, it was seen that the distribution coefficients ( ) of V decrease with an increase in [HCl] (subscript T: total concentration), indicating that the anionic V species such as HVO are exponentially changed into the cationic V species such as V, VO, and VO under the condition [HCl] = 1.0 M, and the complexation reactions between BC15 (or BC18) and the initial V structures are inhibited. Besides, it was reasonably shown that the adsorption mechanism is the path through the electrostatic interaction between the anionic V species such as HVO , and the -C-O-C- single bond that the electron density is eccentrically located in ether functional groups in crown ether rings in BC15 and BC18 (or the -C-OH single bond that the electron density is eccentrically located in bisphenol A in BC15 and BC18). Then, the chromatography experiment of V, U, and Li on BC15 (or BC18) at 298 K was carried out by flowing seawater, 1.0 × 10 M HCl, and 1.0 M HCl in sequence. The first peak of V can be separated from the plateau of Li and the first and second peaks of U in the case of the BC15 system. The recovery ratios of V and U were more than 80%. On the other hand, entirely overlapping chromatograms were obtained in the case of the BC18 system, and accordingly, the recovery ratios of V and U were much lower. In short, the separation efficiency of V with BC15 is more pre-eminent than that with BC18. Judging from these results, the durability of BC15 was finally assessed for industrial applications, that is, the aforementioned chromatography experiment was repeatedly carried out to check whether V, U, and Li were stably and mutually separated from seawater or not. The evidence that the recovery performances of V, U, and Li from seawater do not decrease at all after at least five cycle tests was provided. This indicates that this information will be valuable for the development of a practical chromatographic technology to simultaneously recover V, U, and Li from seawater.
有人提出将由苯并 - 15 - 冠 - 5（简称为BC15）和苯并 - 18 - 冠 - 6（BC18）组成的复合吸附剂用于从海水中同时回收钒（V）、铀（U）和锂（Li），以实现工业应用。已在很宽的温度范围内，在各种类型的水溶液中研究了这些元素在BC15和BC18上的吸附和解吸行为。结果表明，BC15和BC18具有足够的吸附能力，可从海水中同时回收V、U和Li。此外，还发现V的分配系数（ ）随[HCl]（下标T：总浓度）的增加而降低，这表明在[HCl] = 1.0 M的条件下，诸如HVO 的阴离子V物种会指数级地转变为诸如V、VO 和VO 的阳离子V物种，并且BC15（或BC18）与初始V结构之间的络合反应受到抑制。此外，合理地表明吸附机制是通过诸如HVO 的阴离子V物种与BC15和BC18冠醚环中醚官能团上电子密度偏心分布的 -C-O-C- 单键（或BC15和BC18中双酚A上电子密度偏心分布的 -C-OH单键）之间的静电相互作用途径。然后，在298 K下，依次流动海水、1.0×10 M HCl和1.0 M HCl，对BC15（或BC18）上的V、U和Li进行了色谱实验。在BC15体系中，V的第一个峰可以与Li的平台以及U的第一个和第二个峰分离。V和U的回收率超过80%。另一方面，在BC18体系中获得了完全重叠的色谱图，因此，V和U的回收率要低得多。简而言之，BC15对V的分离效率比BC18更为突出。根据这些结果，最终评估了BC15在工业应用中的耐久性，即重复进行上述色谱实验，以检查V、U和Li是否能从海水中稳定且相互分离。提供的证据表明，在至少进行五次循环测试后，从海水中回收V、U和Li的性能根本没有下降。这表明该信息对于开发从海水中同时回收V、U和Li的实用色谱技术将是有价值的。
