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首页> 外文期刊>Environmental Science & Technology >Anaerobic Dissolution Rates of U(Ⅳ)-Oxide by Abiotic and Nitrate-Dependent Bacterial Pathways
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Anaerobic Dissolution Rates of U(Ⅳ)-Oxide by Abiotic and Nitrate-Dependent Bacterial Pathways

机译：无生物和硝酸盐依赖性细菌途径的U（Ⅵ） - 氧化物的厌氧溶解率

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The long-term stability of U(Ⅳ) solid phases in anaerobic aquifers depends upon their reactivity in the presence of oxidizing chemical species and microbial catalysts. We performed flow-through column experiments under anaerobic conditions to investigate the mechanisms and dissolution rates of biogenic, noncrystalline UO_2(s) by chemical oxidants (nitrate and/or nitrite) or by Thiobacillus denitrificans, a widespread, denitrifying, chemolithoautotrophic model bacterium. Dissolution rates of UO_2(s) with dissolved nitrite were approximately 5 to 10 time: greater than with nitrate alone. In the presence of wild-type T. denitrijicans and nitrate, UO_2(s) dissolution rates were similar to those of abiotic experiments with nitrite (from 1.15×10~(-14) to 4.94 × 10~(-13) mol m~(-2) s~(-1)). Experiments with a T. dentrificans mutant strain defective in U(Ⅳ) oxidation supported microbially mediated U(Ⅳ) oxidation. X-ray absorption spectroscopy (XAS) analysis of post-reaction solids showed the presence of mononuclear U(Ⅵ) species rather than a solid U(Ⅵ) phase. At steady-state U release, kinetic and spectroscopic results suggest detachment of oxidized U(Ⅵ) from the UO_2(s) surface as the rate-determining step rather than electron transfer or ion diffusion. Under anaerobic conditions, production of nitrite by nitrate-reducing microorganisms and enzymatically catalyzed, nitrate-dependent U(Ⅳ) oxidation are likely dual processes by which reduced U solids may be oxidized and mobilized in the aqueous phase.
机译：厌氧含水层中U（Ⅵ）固相的长期稳定性取决于它们在氧化化学物质和微生物催化剂存在下的反应性。我们在厌氧条件下进行流动柱实验，以研究生物氧化剂（硝酸盐和/或亚硝酸盐）或硫胞菌，硫胞菌，一种广泛的，反硝化的趋化性模型细菌的机制和溶解速率。用溶解的亚硝酸盐的UO_2（S）的溶解速率约为5至10次：大于单独硝酸盐。在存在野生型的T. dairitjicans和硝酸盐中，UO_2（S）溶解率类似于亚硝酸盐的非生物实验（从1.15×10〜（-14）到4.94×10〜（-13）mol m〜 （-2）S〜（-1））。用T.Dentrificans突变菌株在U（Ⅵ）氧化中缺陷的实验支持微生物介导的U（Ⅵ）氧化。反应后固体的X射线吸收光谱（XAs）分析显示出单核U（Ⅵ）种而不是固体U（Ⅵ）相。在稳态U释放，动力学和光谱结果表明从UO_2表面的氧化U（ⅵ）的分离为速率确定步骤而不是电子传递或离子扩散。在厌氧条件下，通过硝酸盐还原微生物产生亚硝酸盐并酶促催化，硝酸依赖性U（ⅳ）氧化是可能的双工艺，通过该方法可以将其氧化和在水相中氧化和动员。

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  • 来源
    《Environmental Science & Technology》 |2020年第13期|8010-8021|共12页
  • 作者

    Maria P. Asta; Harry R. Beller; Peggy A. ODay;

  • 作者单位

    Sierra Nevada Research Institute University of California Merced Merced California 9S343 United States;

    Lawrence Berkeley National Laboratory Berkeley California 94720 United States Department of Chemical Engineering and Applied Chemistry University of Toronto Toronto Ontario MSS 3E5 Canada;

    Sierra Nevada Research Institute and Department of Life and Environmental Sciences University of California Merced Merced California 9534.3 United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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