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首页> 外文期刊>Environmental Science & Technology >Quantifying Differences in the Impact of Variable Chemistry on Equilibrium Uranium(VI) Adsorption Properties of Aquifer Sediments
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Quantifying Differences in the Impact of Variable Chemistry on Equilibrium Uranium(VI) Adsorption Properties of Aquifer Sediments

机译：定量分析可变化学对含水层沉积物中平衡铀（VI）吸附特性的影响

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摘要

Uranium adsorption-desorption on sediment samples collected from the Hanford 300-Area, Richland, WA varied extensively over a range of field-relevant chemical conditions, complicating assessment of possible differences in equilibrium adsorption properties. Adsorption equilibrium was achieved in 500-1000 h although dissolved uranium concentrations increased over thousands of hours owing to changes in aqueous chemical composition driven by sediment-water reactions. A nonelectrostatic surfece complexation reaction, >SOH + UO_2~(2+) + 2CO_3~(2-) = >SOUO_2(CO_3HCO_3)~(2-) provided the best fit to experimental data for each sediment sample resulting in a range of conditional equilibrium constants (logK~c) from 21.49 to 21.76. Potential differences in uranium adsorption properties could be assessed in plots based on the generalized mass-action expressions yielding linear trends displaced vertically by differences in logK~c values. Using this approach, logK~c values for seven sediment samples were not significantly different However, a significant difference in adsorption properties between one sediment sample and the fines (<0.063 mm) of another could be demonstrated despite the fines requiring a different reaction stoichiometry. Estimates of log~c uncertainty were improved by capturing all data points within experimental errors. The mass-action expression plots demonstrate that applying models outside the range of conditions used in model calibration greatly increases potential errors.
机译：在与田野有关的化学条件范围内，从华盛顿州里奇兰市汉福德300区的沉积物样品上进行的铀吸附-解吸变化很大，这使得平衡吸附特性可能存在差异的评估变得复杂。在500-1000小时内达到了吸附平衡，尽管由于沉积物-水反应驱动了水化学成分的变化，溶解铀的浓度在数千小时内增加了。 > SOH + UO_2〜（2+）+ 2CO_3〜（2-）=> SOUO_2（CO_3HCO_3）〜（2-）的非静电表面络合反应最适合每个沉积物样品的实验数据，从而产生了一系列条件平衡常数（logK〜c）从21.49至21.76。铀吸附特性的潜在差异可以在图表上基于广义质量作用表达式进行评估，该表达式产生线性趋势，其线性变化趋势由logK〜c值的差异引起。使用这种方法，七个沉积物样品的logK〜c值没有显着差异。然而，尽管细粉需要不同的反应化学计量，但一个沉积物样品与另一个沉积物的细粉（<0.063 mm）之间的吸附性能存在显着差异。通过捕获实验误差内的所有数据点，可以改善对数不确定性的估计。质量作用表达式图表明，在模型校准所用条件范围之外应用模型会大大增加潜在误差。

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  • 来源
    《Environmental Science & Technology》 |2011年第20期|p.8733-8740|共8页
  • 作者

    Deborah L. Stoliker; Douglas B. Kent; John M. Zachara;

  • 作者单位

    U.S. Geological Survey, 345 Middlefield Rd. MS 496, Menlo Park, California 94025, United States;

    U.S. Geological Survey, 345 Middlefield Rd. MS 496, Menlo Park, California 94025, United States;

    Pacific Northwest National Laboratory, Richland, Washington, 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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