Coupled stream-subsurface exchange of colloidal hematite and dissolved zinc, copper, and phosphate.
Coupled stream-subsurface exchange of colloidal hematite and dissolved zinc, copper, and phosphate.
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DOI：
10.1021/es050168q
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发表时间：
2005-07
影响因子：
11.4
通讯作者：
Jianhong Ren;A. Packman
中科院分区：
文献类型：
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作者：
Jianhong Ren;A. Packman
以前的研究表明，河流-地下交换对河流中胶体和反应性溶质的传输都具有重要的意义，因为它增加了河流生成的物质与底质相互作用的机会。我们在实验室进行了一系列水槽实验，研究了赤铁矿与吸附溶质锌、铜和磷酸盐的流-地下耦合交换。采用基于过程的基本输运模型对实验结果进行了分析。我们发现赤铁矿对所有被测离子的迁移都有显著的影响。此外，这些溶质的存在大大改变了赤铁矿的流动性。批式和柱式实验表明，赤铁矿活动性的差异是锌、铜和磷酸盐吸附到赤铁矿表面的直接影响。吸附很大程度上改变了赤铁矿的表面电荷，进而改变了赤铁矿的过滤行为。这些结果表明，污染物的行为不能与地表水和地下水系统中的胶体分开分析，因为表面化学过程可能导致它们的行为耦合。特别是，我们的结果表明，污染物和氧化铁颗粒之间的一般和特定的相互作用可以改变胶体的流动性，扰乱自然的细颗粒动力学，并有利于或不利于污染物的流动性。
Previous studies have shown that stream-subsurface exchange has important implications for both colloid and reactive solute transport in streams because it increases the opportunity for the interaction of stream-born substances with bed sediments. We executed a series of laboratory flume experiments to study the coupled stream-subsurface exchange of hematite and the sorbing solutes zinc, copper, and phosphate. A fundamental process-based transport model was applied to analyze the experimental results. We found that hematite had a significant effect on the transport of all ions tested. In addition, hematite mobility was substantially modified by the presence of these solutes. Batch and column experiments showed that the difference in hematite mobility was a direct effect of zinc, copper, and phosphate sorption to the hematite surface. Sorption substantially modified the hematite surface charge and subsequently hematite filtration behavior. These results suggest that the behavior of contaminants cannot be analyzed separately from colloids in surface and groundwater systems because surface-chemical processes can cause their behavior to be coupled. In particular, our results show that general and specific interactions between contaminants and iron oxide particles can alter colloid mobility, perturb natural fine particle dynamics, and either favor or disfavor contaminant mobility.