Sorption-desorption of lead (II) and mercury (II) by model associations of soil colloids
Sorption-desorption of lead (II) and mercury (II) by model associations of soil colloids
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DOI：
10.2136/sssaj2003.1378
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发表时间：
2003-09-01
影响因子：
2.9
通讯作者：
Cornejo, J
中科院分区：
文献类型：
--
作者：
Cruz-Guzmán, M;Celis, R;Cornejo, J
土壤胶体的吸附很大程度上决定了重金属的生物利用度及其在土壤和水生环境中的移动。由于土壤成分的相互作用，天然土壤胶体的吸附行为可能不对应于其各个成分的简单总和。在这项工作中，研究了含有怀俄明州蒙脱石 (SW)、不良结晶水铁矿 (Ferrih) 和土壤腐殖酸 (HA) 的二元和三元模型颗粒对 Pb(II) 和 Hg(II) 离子的吸附，并将所得结果与各个成分的吸附行为进行了比较。对于单一吸附剂，HA 上的 Pb(II) 吸附量较高，SW 上的吸附量中等，Ferrih 上的吸附量为零，而 Hg(II) 吸附量按以下顺序降低：HA >> Ferrih > SW。 SW 上的水铁矿涂层对粘土吸附 Pb(II) 和 Hg(II) 的影响很小。 SW 上的腐殖酸涂层显着增强了两种重金属的吸附，而出乎意料的是，Ferrih 上的 HA 涂层并未增强重金属吸附。最后的结果归因于 HA 负责重金属吸附的官能团（例如羧基）由于与 Ferrih 表面相互作用而被阻断。在含有 HA 的三元颗粒中观察到 Pb(II) 的类似行为。模型协会的吸附是高度可逆的。这项研究的结果证实，胶体颗粒对重金属的吸附行为并不是单一成分贡献的简单总和，这表明考虑多相模型吸附剂对于实现对土壤吸附过程更现实的解释是有用的。
Sorption by soil colloids largely determines the bioavailability of heavy metals and their movement in soil and aquatic environments. Due to soil constituents' interactions, the sorption behavior of natural soil colloids may not correspond to the simple sum of their individual constituents. In this work, sorption of Pb(II) and Hg(II) ions by binary and ternary model particles containing Wyoming montmorillonite (SW), poorly crystallized ferrihydrite (Ferrih), and soil humic acid (HA) was investigated and the results obtained were compared with the sorption behavior of the individual constituents. For single sorbents, Pb(II) sorption was high on HA, moderate on SW and zero on Ferrih, whereas Hg(II) sorption decreased in the order: HA >> Ferrih > SW. Ferrihydrite coatings on SW had little effect on Pb(II) and Hg(II) sorption by the clay. Humic acid coatings on SW significantly enhanced sorption of both heavy metals, whereas, unexpectedly, HA coatings on Ferrih did not enhance heavy metal sorption. This last result was attributed to blockage of the functional groups of HA responsible for heavy metal sorption (such as carboxylic groups) as a result of their interaction with the Ferrih surface. A similar behavior was observed for Pb(II) in ternary particles containing HA. Sorption by the model associations was highly reversible. The results of this study confirmed that the sorptive behavior of colloidal particles for heavy metals is not the simple sum of the contributions of the single constituents, indicating the usefulness of considering polyphasic model sorbents to achieve a more realistic interpretation of the sorption process in soil.