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首页> 外文期刊>Environmental Science & Technology >Interactions of Trace Metals with Hydrogels and Filter Membranes Used in DET and DGT Techniques
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Interactions of Trace Metals with Hydrogels and Filter Membranes Used in DET and DGT Techniques

机译：痕量金属与DET和DGT技术中使用的水凝胶和滤膜的相互作用

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Equilibrium partitioning of trace metals between bulk solution and hydrogels/filter was studied. Under some conditions, trace metal concentrations were higher in the hydrogels or filter membranes compared to bulk solution (enrichment). In synthetic soft water, enrichment of cationic trace metals in polyacrylamide hydrogels decreased with increasing trace metal concentration. Enrichment was little affected by Ca and Mg in the concentration range typically encountered in natural freshwaters, indicating high affinity but low capacity binding of trace metals to solid structure in polyacrylamide gels. The apparent binding strength decreased in the sequence: Cu > Pb > Ni ≈ Cd ≈ Co and a low concentration of cationic Cu eliminated enrichment of weakly binding trace metal cations. The polyacrylamide gels also had an affinity for fulvic acid and/or its trace metal complexes. Enrichment of cationic Cd in agarose gel and hydrophilic polyethersulfone filter was independent of concentration (10 nM to 5 μM) but decreased with increasing Ca/ Mg concentration and ionic strength, suggesting that it is mainly due to electrostatic interactions. However, Cu and Pb were enriched even after equilibration in seawater, indicating that these metals additionally bind to sites within the agarose gel and filter. Compared to the polyacrylamide gels, agarose gel had a lower affinity for metal-fulvic complexes. Potential biases in measurements made with the diffusive equilibration in thin-films (DET) technique, identified by this work, are discussed.
机译：研究了本体溶液与水凝胶/过滤器之间痕量金属的平衡分配。在某些条件下，与本体溶液（富集）相比，水凝胶或滤膜中的痕量金属浓度更高。在合成软水中，聚丙烯酰胺水凝胶中阳离子痕量金属的富集随着痕量金属浓度的增加而降低。钙和镁在天然淡水中通常遇到的浓度范围内富集几乎没有影响，表明聚丙烯酰胺凝胶中痕量金属与固体结构的亲和力高但结合力低。表观结合强度依次降低：Cu> Pb> Ni≈Cd≈Co，并且低浓度的阳离子Cu消除了弱结合的痕量金属阳离子的富集。聚丙烯酰胺凝胶还对黄腐酸和/或其痕量金属络合物具有亲和力。琼脂糖凝胶和亲水性聚醚砜滤池中阳离子Cd的富集与浓度（10 nM至5μM）无关，但随着Ca / Mg浓度和离子强度的增加而降低，表明这主要是由于静电相互作用。但是，即使在海水中平衡后，Cu和Pb也会富集，表明这些金属还与琼脂糖凝胶和过滤器中的位点结合。与聚丙烯酰胺凝胶相比，琼脂糖凝胶对金属-富维夫配合物的亲和力较低。讨论了通过这项工作确定的利用薄膜中的扩散平衡（DET）技术进行的测量中的潜在偏差。

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