Organic Functional Group Chemistry in Mineralized Deposits Containing U(IV) and U(VI) from the Jackpile Mine in New Mexico.
Organic Functional Group Chemistry in Mineralized Deposits Containing U(IV) and U(VI) from the Jackpile Mine in New Mexico.
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DOI：
10.1021/acs.est.9b00407
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发表时间：
2019-04
影响因子：
11.4
通讯作者：
C. A. Velasco;K. Artyushkova;A. Ali;C. Osburn;Jorge Gonzalez-Estrella;J. Lezama-Pacheco;S. Cabaniss;J. Cerrato
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文献类型：
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作者：
C. A. Velasco;K. Artyushkova;A. Ali;C. Osburn;Jorge Gonzalez-Estrella;J. Lezama-Pacheco;S. Cabaniss;J. Cerrato
我们调查了天然有机物（NOM）与U（IV）和U（VI）的固体矿化矿床暴露于氧化条件下，从Jackpile矿，拉古纳普韦布洛，NM的官能团化学。通过X射线荧光法测定未反应样品中铀（U）含量为0.44-2.6%（重量）。尽管长时间暴露于环境氧化条件下，但在U LIII边扩展X射线吸收精细结构谱上识别出约49%的U（IV）和约51%的U（VI）。烧失量和热重分析确定从13%至44%的NOM的样品。通过拟合高分辨率X射线光电子能谱（XPS）的C 1 s和O 1 s谱，确定了未反应的样品中的羰基，酚类和羧基官能团。对应于酚和羰基官能团的峰的强度高于来自在pH 13、7和2下进行的分批提取的上清液中的样品中对应于羧基的峰的强度。通过拟合高分辨率XPS U 4f谱，在氧化条件下进行分批萃取后，在上清液中检测到U（IV）和U（VI）物种。这项研究的结果突出了pH值对矿化矿床中有机官能团化学和U形态的影响的重要性。
We investigated the functional group chemistry of natural organic matter (NOM) associated with both U(IV) and U(VI) in solids from mineralized deposits exposed to oxidizing conditions from the Jackpile Mine, Laguna Pueblo, NM. The uranium (U) content in unreacted samples was 0.44-2.6% by weight determined by X-ray fluorescence. In spite of prolonged exposure to ambient oxidizing conditions, ≈49% of U(IV) and ≈51% of U(VI) were identified on U LIII edge extended X-ray absorption fine structure spectra. Loss on ignition and thermogravimetric analyses identified from 13% to 44% of NOM in the samples. Carbonyl, phenolic, and carboxylic functional groups in the unreacted samples were identified by fitting of high-resolution X-ray photoelectron spectroscopy (XPS) C 1s and O 1s spectra. Peaks corresponding to phenolic and carbonyl functional groups had intensities higher than those corresponding to carboxylic groups in samples from the supernatant from batch extractions conducted at pH 13, 7, and 2. U(IV) and U(VI) species were detected in the supernatant after batch extractions conducted under oxidizing conditions by fitting of high-resolution XPS U 4f spectra. The outcomes from this study highlight the importance of the influence of pH on the organic functional group chemistry and U speciation in mineralized deposits.