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首页> 外文期刊>Environmental Science & Technology >Clarithromycin and Tetracycline Binding to Soil Humic Acid in the Absence and Presence of Calcium
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Clarithromycin and Tetracycline Binding to Soil Humic Acid in the Absence and Presence of Calcium

机译：钙的存在与不存在下克拉霉素和四环素与土壤腐殖酸的结合

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摘要

Numerous ionizable organic micropollutants contain positively charged moieties at pH values typical of environmental systems. Describing organic cation and zwitterion interaction with dissolved natural organic matter requires explicit consideration of the pH-dependent speciation of both sorbate and sorbent. We studied the pH-, ionic strength-, and concentration-dependent binding of relatively large, organic cations and zwitterions (viz., the antibiotics clarithromycin and tetracycline) to dissolved humic acid in the absence and presence of Ca~(2+) and evaluated the ability of the NICA-Donnan model to describe the data. Clarithromycin interaction with dissolved humic acid was well described by the model including the competitive effect of Ca~(2+) on clarithromycin binding over a wide range of solution conditions by considering only the binding of the cationic species to low proton-affinity sites in humic acid. Tetracycline possesses multiple ionizable moieties and forms complexes with Ca~(2+). An excellent fit to experimental data was achieved by considering tetracycline cation interaction with both low and high proton- affinity sites of humic acid and zwitterion interaction with high proton-affinity sites. In contrast to clarithromycin, tetracycline binding to humic acid increased in the presence of Ca~(2+), especially under alkaline conditions. Model calculations indicate that this increase is due to electrostatic interaction of positively charged tetracycline-Ca complexes with humic acid rather than due to the formation of ternary complexes, except at very low TC concentrations.
机译：在环境系统的典型pH值下，许多可电离的有机微污染物都包含带正电的部分。描述有机阳离子和两性离子与溶解的天然有机物的相互作用需要明确考虑山梨酸盐和吸附剂的pH依赖性物种。我们研究了在不存在和存在Ca〜（2+）和Ca〜（2+）的情况下，相对较大的有机阳离子和两性离子（即抗生素克拉霉素和四环素）与溶解的腐殖酸的pH，离子强度和浓度依赖性结合。评估了NICA-Donnan模型描述数据的能力。该模型很好地描述了克拉霉素与腐殖酸的相互作用，包括仅考虑阳离子物种与腐殖质中低质子亲和力部位的结合，Ca〜（2+）在广泛溶液条件下对克拉霉素的竞争作用。酸。四环素具有多个可电离的部分，并与Ca〜（2+）形成配合物。通过考虑四环素阳离子与腐殖酸的低质子亲和力位点和高质子亲和力位点的相互作用以及两性离子与高质子亲和力位点的相互作用，可以很好地拟合实验数据。与克拉霉素相反，在Ca〜（2+）存在下，尤其是在碱性条件下，四环素与腐殖酸的结合增加。模型计算表明，这种增加是由于带正电的四环素-Ca复合物与腐殖酸的静电相互作用，而不是由于三元复合物的形成，除非在非常低的TC浓度下。

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  • 来源
    《Environmental Science & Technology》 |2016年第18期|9933-9942|共10页
  • 作者

    Iso Christl; Mercedes Ruiz; J.R. Schmidt; Joel A. Pedersen;

  • 作者单位

    Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, 8092 Zuerich, Switzerland;

    Environmental Chemistry and Technology Program, University of Wisconsin, Madison, Wisconsin 53706, United States;

    Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States;

    Environmental Chemistry and Technology Program, University of Wisconsin, Madison, Wisconsin 53706, United States,Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States,Department of Soil Science, University of Wisconsin, Madison, Wisconsin 53706, 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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