Subsurface migration of copper and zinc mediated by soil colloids
Subsurface migration of copper and zinc mediated by soil colloids
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DOI：
10.2136/sssaj1999.634830x
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发表时间：
1999-07-01
影响因子：
2.9
通讯作者：
Karathanasis, AD
中科院分区：
文献类型：
--
作者：
Karathanasis, AD
胶体在地下环境中的迁移引起了人们的特别关注，因为它被怀疑在促进污染物向地下水的迁移中起着重要作用。研究了不同组成的水分散性土壤胶体（WDC）在原状土柱中迁移Cu和Zn的可能作用。铜或锌的解决方案，没有胶体（对照），并与蒙脱石，混合，伊利石和高岭石胶体与一系列的表面性质的悬浮液相结合，施加在一个恒定的nux到原状土柱。土柱代表上土层的Maury（细，混合，中典型Paleudalf）和Loradale（细粉质，混合，中典型Argiudoll）土壤的孔隙度和有机C（OC）含量的对比。在洗脱液中的胶体和金属回收率随金属，胶体和土壤性质而变化。胶体的存在下，通常增强金属传输的5- 50倍以上的控制处理，与锌一贯更移动的比铜。具有高负表面电荷和OC含量的胶体表现出最大的金属传输电位，而具有大粒径、低负表面电荷和高Fe-和Al-羟基氧化物含量的胶体表现出最低的金属传输电位。虽然占主导地位的运输机制马斯金属吸附胶体和共运输，额外的可溶性铜和锌运输胶体的存在下，表明参与物理排斥，竞争吸附，或增加金属溶解过程。土壤柱中OC含量的增加似乎掩盖了大孔隙对两种金属，特别是铜的运输的影响。这些研究结果对污染物迁移预测模型的使用和有效补救技术的应用具有重要影响。
Colloid migration in subsurface environments has attracted special attention lately because of its suspected role in facilitating transport of contaminants to groundwater. This study investigated the potential role of water-dispersible soil colloids (WDCs) with variable composition in transporting Cu and Zn through undisturbed soil columns. Copper or Zn solutions without colloids (controls) and combined with suspensions of montmorillonitic, mixed, illitic, and kaolinitic colloids with a range of surface properties were applied at a constant nux into undisturbed soil columns. The soil columns represented upper solum horizons of Maury (fine, mixed, mesic Typic Paleudalf) and Loradale (fine-silty, mixed, mesic Typic Argiudoll) soils with contrasting porosities and organic C (OC) contents. Colloid and metal recoveries in the eluent varied with metal, colloid, and soil properties. The presence of colloids typically enhanced metal transport by 5- to 50-fold over that of the control treatments, with Zn being consistently more mobile than Cu. The greatest metal transport potential was shown by colloids with high negative surface charge and OC content and the lowest by colloids with large particle size, low negative surface charge, and high Fe- and Al-hydroxyoxide contents. Although the dominant transport mechanism mas metal sorption by colloids and cotransport, the additional soluble Cu and Zn transported in the presence of colloids suggests involvement of physical exclusion, competitive sorption, or increased metal solubilization processes. Increased amounts of OC content in the soil column appeared to overshadow the effects of macroporosity on the transport of both metals, especially Cu. These findings have important ramifications on the use of contaminant transport prediction models and the application of efficient remediation technologies.