College of Architecture and Environment & Healthy Food Evaluation Research Center, Sichuan University, Chengdu, 610065, China.
Key Laboratory of Environment Remediation and Ecological Health (Zhejiang University), Ministry of Education, Hangzhou, 310058, China.
Environ Sci Pollut Res Int. 2020 May;27(15):17910-17922. doi: 10.1007/s11356-020-07845-x. Epub 2020 Mar 12.
Vanadium (V) pollution in soil has been widely noted, while knowledge about the effect of soil colloid on migration of V is scarce. Batch adsorption-desorption and transportation of the colloid-adsorbed V in columns packed with quartz sand under various environment conditions were carried out to explore the retention and transportation of V by colloidal kaolinite. Batch adsorption-desorption studies show that the adsorption of V by the colloidal kaolinite was mainly specific adsorption and redox played a limited role in the adsorption process. The maximum adsorption capacity of the colloidal kaolinite was 712.4 mg g, and about 5.9-8.7% of the adsorbed V could be desorbed. Both the adsorption-desorption and migration of V with colloidal kaolinite were highly ambient condition dependent. The column studies show that V was highly mobile in the saturated porous media. An easier transfer of V with an increase in pH, IS, and velocity of flow was noted. However, the increase of IS lead to the blockage of the colloidal kaolinite transportation. The recovery rate of the colloidal kaolinite at pH 7 and 9 was 2.0 and 2.1 times that at pH 5, respectively. The migration of colloidal-adsorbed V in sand column preceded that of V ion, but more colloidal-bound V than V ion remained in the column. Lack of consideration of the combination and co-transportation of V and colloidal kaolinite will lead to an overestimation of the risk of V to deeper soil profiles and groundwater. Graphical abstract.
土壤中钒（V）的污染已受到广泛关注，而关于土壤胶体对 V 迁移影响的知识却很少。通过在石英砂柱中进行的一系列环境条件下的胶体吸附 V 的批量吸附-解吸和运移实验，研究了胶体高岭石对 V 的保留和运移。批量吸附-解吸实验表明，胶体高岭石对 V 的吸附主要是特异吸附，而氧化还原作用在吸附过程中作用有限。胶体高岭石的最大吸附容量为 712.4mg/g，约有 5.9-8.7%的吸附 V 可以解吸。胶体高岭石对 V 的吸附-解吸和运移均高度依赖环境条件。柱实验表明，V 在饱和多孔介质中具有很强的迁移性。随着 pH 值、离子强度和流速的增加，V 的迁移能力增强。然而，离子强度的增加导致胶体高岭石的运移受阻。在 pH 值为 7 和 9 时，胶体高岭石的回收率分别为 pH 值为 5 时的 2.0 和 2.1 倍。胶体吸附 V 在砂柱中的迁移先于 V 离子，但在柱中残留的胶体结合态 V 比 V 离子多。如果不考虑 V 和胶体高岭石的结合和共同运移，将会高估 V 对深层土壤剖面和地下水的风险。图摘要。
