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首页> 外文期刊>Environmental Science & Technology >The Role of Defects in Fe(Ⅱ)-Goethite Electron Transfer
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The Role of Defects in Fe(Ⅱ)-Goethite Electron Transfer

机译：缺陷在Fe（Ⅱ）-针铁矿电子转移中的作用

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Despite substantial experimental evidence for Fe(II)–Fe(III) oxide electron transfer, computational chemistry calculations suggest that oxidation of sorbed Fe(II) by goethite is kinetically inhibited on structurally perfect surfaces. We used a combination of ~(57)Fe Mössbauer spectroscopy, synchrotron X-ray absorption and magnetic circular dichroism (XAS/XMCD) spectroscopies to investigate whether Fe(II)–goethite electron transfer is influenced by defects. Specifically, Fe L-edge and O K-edge XAS indicates that the outermost few Angstroms of goethite synthesized by low temperature Fe(III) hydrolysis is iron deficient relative to oxygen, suggesting the presence of defects from Fe vacancies. This nonstoichiometric goethite undergoes facile Fe(II)–Fe(III) oxide electron transfer, depositing additional goethite consistent with experimental precedent. Hydrothermal treatment of this goethite, however, appears to remove defects, decrease the amount of Fe(II) oxidation, and change the composition of the oxidation product. When hydrothermally treated goethite was ground, surface defect characteristics as well as the extent of electron transfer were largely restored. Our findings suggest that surface defects play a commanding role in Fe(II)–goethite redox interaction, as predicted by computational chemistry. Moreover, it suggests that, in the environment, the extent of this interaction will vary depending on diagenetic history, local redox conditions, as well as being subject to regeneration via seasonal fluctuations.
机译：尽管有大量实验证明了Fe（II）–Fe（III）氧化物电子转移，但化学计算结果表明，针铁矿对吸附的Fe（II）的氧化在动力学上抑制了结构完美的表面。我们结合使用了〜（57）FeMössbauer光谱，同步加速器X射线吸收和磁圆二色性（XAS / XMCD）光谱，研究了Fe（II）-针铁矿电子传递是否受缺陷影响。具体而言，Fe L边缘和O K边缘XAS表明通过低温Fe（III）水解合成的针铁矿的最外层埃相对于氧气而言是铁缺乏的，这表明存在着来自铁空位的缺陷。这种非化学计量的针铁矿经历了容易的Fe（II）–Fe（III）氧化物电子转移，沉积了与实验先例相符的针铁矿。然而，对该针铁矿的水热处理似乎去除了缺陷，减少了Fe（II）的氧化量，并改变了氧化产物的组成。将经过水热处理的针铁矿进行研磨后，表面缺陷特征以及电子转移程度得到了很大程度的恢复。我们的发现表明，表面缺陷在Fe（II）-针铁矿氧化还原相互作用中起着主导作用，正如计算化学所预测的那样。此外，这表明，在环境中，这种相互作用的程度将取决于成岩史，局部氧化还原条件以及由于季节性波动而再生。

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  • 来源
    《Environmental Science & Technology》 |2018年第5期|2751-2759|共9页
  • 作者

    Luiza Notini; Drew E. Latta; Anke Neumann; Carolyn I. Pearce; Michel Sassi; Alpha T. N’Diaye; Kevin M. Rosso; Michelle M. Scherer;

  • 作者单位

    Department of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa 52242, United States;

    Department of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa 52242, United States;

    School of Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom;

    Pacific Northwest National Laboratory, Richland, Washington 99352, United States;

    Pacific Northwest National Laboratory, Richland, Washington 99352, United States;

    Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States;

    Pacific Northwest National Laboratory, Richland, Washington 99352, United States;

    Department of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa 52242, 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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