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首页> 外文期刊>Environmental Science & Technology >Molecular Fractionation of Dissolved Organic Matter with Metal Salts
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Molecular Fractionation of Dissolved Organic Matter with Metal Salts

机译：金属盐溶解的有机物的分子分级分离

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Coagulation of dissolved organic matter (DOM) by hydro-lyzing metals is an important environmental process with particular relevance, e.g., for the cycling of organic matter in metal-rich aquatic systems or the flocculation of organic matter in wastewater treatment plants. Often, a nonremovable fraction of DOM remains in solution even at low DOM/metal ratios. Because coagulation by metals results from interactions with functional groups, we hypothesize that noncoagulating fractions have a distinct molecular composition. To test the hypothesis, we analyzed peat-derived dissolved organic matter remaining in solution after mixing with salts of Ca, Al, and Fe using 15 T Electrospray Ionization Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (ESI-FT-ICR-MS). Addition of metals resulted in a net removal of DOM. Also a reduction of molecular diversity was observed, as the number of peaks from the ESI-FT-ICR-MS spectra decreased. At DOM/metal ratios of ～9 Ca did not show any preference for distinct molecular fractions, while Fe and Al removed preferentially the most oxidized compounds (O/C ratio >0.4) of the peat leachate. Lowering DOM/metal ratios to ～1 resulted in further removal of less oxidized as well as more aromatic compounds ("black carbon"). Molecular composition in the residual solution after coagulation was more saturated, less polar, and less oxidized compared to the original peat leachate and exhibited a surprising similarity with DOM of marine origin. By identifying more than 9200 molecular formulas we can show that structural properties (saturation and aromatictty) and oxygen content of individual DOM molecules play an important role in coagulation with metals. We conclude that polyvalent cations not only alter the net mobility but also the very molecular composition of DOM in aquatic environments.
机译：通过水解金属而使溶解的有机物（DOM）凝结是一个重要的环境过程，具有特殊的意义，例如，对于富金属水生系统中有机物的循环或废水处理厂中有机物的絮凝。通常，即使在低DOM /金属比的情况下，DOM中也有不可除去的部分保留在溶液中。由于金属的凝结是与官能团相互作用的结果，因此我们假设非凝结部分具有独特的分子组成。为了验证该假设，我们使用15 T电喷雾电离傅里叶变换离子回旋共振质谱（ESI-FT-ICR-MS）分析了与Ca，Al和Fe的盐混合后残留在溶液中的泥炭衍生的溶解有机物。金属的添加导致DOM的净去除。此外，随着ESI-FT-ICR-MS光谱中峰数的减少，观察到了分子多样性的降低。在DOM /金属比为〜9时，Ca并未显示出对不同分子部分的偏好，而Fe和Al则优先去除了泥炭渗滤液中氧化程度最高的化合物（O / C比> 0.4）。将DOM /金属比降低到〜1可以进一步去除较少的氧化以及更多的芳族化合物（“黑碳”）。与原始泥炭浸出液相比，凝结后残留溶液中的分子组成更饱和，极性更弱，氧化更少，并且与海洋来源的DOM表现出惊人的相似性。通过鉴定超过9200个分子式，我们可以证明单个DOM分子的结构性质（饱和度和芳族化合物）和氧含量在与金属的凝结中起重要作用。我们得出的结论是，在水生环境中，多价阳离子不仅会改变净迁移率，而且会改变DOM的分子组成。

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  • 来源
    《Environmental Science & Technology》 |2012年第8期|p.4419-4426|共8页
  • 作者

    Thomas Riedel; Harald Biester; Thorsten Dittmar;

  • 作者单位

    Institut fuer Geooekologie, Technische Universitaet Braunschweig, 38106 Braunschweig, Deutschknd;

    Institut fuer Geooekologie, Technische Universitaet Braunschweig, 38106 Braunschweig, Deutschknd;

    Max Planck Research Group for Marine Geochemistry, University of Oldenburg, Institute for Chemistry and Biology of the Marine Environment, 26129 Oldenburg, Germany and Max Planck Institute for Marine Microbiology, 28359 Bremen, Germany;

  • 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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