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首页> 外文期刊>Environmental Science & Technology >In-Situ Speciation of Ni and Zn in Freshwaters: Comparison between DGT Measurements and Speciation Models
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In-Situ Speciation of Ni and Zn in Freshwaters: Comparison between DGT Measurements and Speciation Models

机译：淡水中镍和锌的原位形态：DGT测量和形态模型之间的比较

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摘要

The technique of DGT (diffusive gradients in thin films) was used for the first time to measure in situ the distribution of Zn and Ni between inorganic species and complexes with fulvic and humic acids in natural waters. With DGT, metals are bound to a resin embedded in a layer of hydrogel after diffusive transport through an adjacent layer of hydrogel. The metal concentrations in the waters can be quantified using simple diffusion equations. By using devices with hydrogels of different pore size, large and small complex species were discriminated. Inorganic species diffuse freely through all gels, but larger organic complexes with fulvic and humic acids diffuse less freely through more restricted gels (gels with smaller pore size). Systematic differences between DGT devices containing gels of different pore size were obtained. Their calibration for the diffusion of fulvic and humic complexes allowed calculation of the concentrations of labile inorganic (Zn, 34.6±2.5 nM; Ni, 23.5±0.9 nM) and labile organic (Zn, 43.1±2.9 nM; Ni, 11.2±0.7 nM) complexes. The concentration of Zn measured by anodic stripping voltammetry in samples returned to the laboratory lay between the DGT-measured inorganic concentration and the total dissolved concentration, consistent with partial measurement of organic complexes of Zn. The speciation model WHAM successfully predicted the species distribution of Ni, Zn, and Cu, provided that competitive binding by Fe(III) was considered. Using the speciation models WHAM and ECOSAT, free ion activities of Zn and Ni were calculated from (1) the total inorganic species measured by DGT and (2) the total dissolved species and dissolved organic carbon. The calculations confirmed the good model predictions of metal-humic binding but highlighted problems with default databases used for the speciation of inorganic components.
机译：首次使用DGT（薄膜中的扩散梯度）技术，在自然水中原位测量无机物种与黄腐酸和腐殖酸复合物之间Zn和Ni的分布。使用DGT，在扩散穿过相邻的水凝胶层后，金属会与嵌入水凝胶层中的树脂结合。水中的金属浓度可以使用简单的扩散方程来量化。通过使用具有不同孔径的水凝胶的装置，可以区分大大小小的复杂物种。无机物质可在所有凝胶中自由扩散，而较大的有机化合物与黄腐酸和腐殖酸则通过较受限制的凝胶（孔径较小的凝胶）自由扩散。获得了包含不同孔径的凝胶的DGT装置之间的系统差异。通过对黄腐和腐殖质复合物扩散进行校准，可以计算出不稳定的无机（Zn，34.6±2.5 nM； Ni，23.5±0.9 nM）和不稳定的有机物（Zn，43.1±2.9 nM； Ni，11.2±0.7 nM）的浓度。 ）复合体。通过阳极溶出伏安法测定的返还实验室样品中的锌浓度介于DGT测量的无机浓度和总溶解浓度之间，这与部分有机锌配合物的测量相符。物种模型WHAM成功地预测了Ni，Zn和Cu的物种分布，前提是要考虑到Fe（III）的竞争结合。使用形态模型WHAM和ECOSAT，由（1）通过DGT测量的总无机物种和（2）总溶解物种和溶解有机碳计算出Zn和Ni的自由离子活性。计算结果证实了金属与腐殖质结合的良好模型预测，但突出了用于无机组分形成的默认数据库存在的问题。

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  • 来源
    《Environmental Science & Technology》 |2004年第5期|p.1421-1427|共7页
  • 作者

    HAO ZHANG;

  • 作者单位
  • 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);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境化学;
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