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| Cr（Ⅵ）一维和二维运移：介质和盐浓度异质性的影响 |
| One dimensional and two-dimensional transport of Cr（Ⅵ）: Effects of medium and salinity heterogeneity |
| 投稿时间：2026-04-05 修订日期：2026-05-13 |
| DOI： |
| 中文关键词: 六价铬 一维/二维运移 水化学条件 介质条件 两点动力学模型 |
| 英文关键词: Hexavalent chromium One-dimensional/two-dimensional transport Hydrochemical conditions Medium conditions Two-site kinetic model |
| 基金项目:江苏省333人才项目（2022-2026）；国家重点研发计划项目（2018YFC1800600） |
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| 中文摘要: |
| 本文利用土柱实验探究不同流速、pH及离子强度条件下来源于搬迁场地的不同深度的三种介质中外源Cr（Ⅵ）的一维运移；利用薄层土箱实验探究地下水盐浓度波动耦合降水条件下Cr（Ⅵ）的二维运移。结果表明介质的异质性影响运移，不同介质中其分配系数不同。长距离的纵向运移的模拟表明，外源Cr（Ⅵ）污染输入5年之后地下20 m左右的深度孔隙水Cr浓度最高，约22.01 mg·L-1，污染深度可扩展至50? m。吸附态Cr的分布明显受到介质层状分布的影响，可能在不同介质界面发生积累。离子强度（5 mM、10 mM）影响运移过程中孔隙水中的Cr浓度。地下水中显著的盐浓度波动的冲击使出流液中Cr浓度发生明显波动。实验pH 4~6范围内，pH对Cr（Ⅵ）的运移影响不明显。Cr（Ⅵ）的一维运移中，流速从0.1 mL·min-1增加到0.2 mL·min-1，其运移时间缩短，但穿透曲线的形状并未发生明显变化。二维运移中，Cr（Ⅵ）随流体由于流体重力向下的运移、随地下水水平流而发生的水平迁移以及在土壤表层发生的水平方向的扩散决定了其污染羽的形状与大小。二维运移过程中地下水出流液中Cr（Ⅵ）浓度随盐浓度的波动与Ni（Ⅱ）不同；其二维迁移形成的污染羽与Ni（Ⅱ）也明显不同。当存在Cr（Ⅵ）与重金属阳离子复合污染时，应谨慎制定环境管理和环境修复策略。 |
| 英文摘要: |
| The one-dimensional transport of exogenous Cr(VI) in three different media originating from different depths of a relocation site under different flow velocities, pH values, and ionic strengths was explored with column experiments. The two-dimensional transport of exogenous Cr(VI) under groundwater salinity fluctuations coupled with rainfall was investigated using a thin box. The results indicated that the heterogeneity of the media affected the transport of Cr(VI), and its partition coefficient varied in different media. The simulation of long-distance vertical transport showed that 5 years after the input of exogenous Cr(VI), the Cr concentration in pore water reached the maximum value of about 22.01 mg·L-1 at a depth of approximately 20 m, and the pollution plume extended to a depth of 50 m. The distribution of adsorbed Cr was obviously affected by the layered distribution of the media, showing accumulation at the interface between different media. Ionic strength (5 mM and 10 mM) affected Cr concentration in pore water during transport, and the significant salinity alteration of groundwater caused fluctuations of Cr concentration in the outflow of groundwater. Within the experimental pH range of 4~6, the effect of pH on the transport of Cr(VI) was slight. In the one-dimensional transport of Cr(VI), as the flow velocity increased from 0.1 to 0.2 mL·min-1, the transport time shortened, but the shape of the penetration curve almost did not change. The shape and size of the pollution plume of Cr(VI) in two-dimensional transport were determined by the downward movement of the fluid due to gravity, horizontal migration caused by groundwater flow, and horizontal diffusion near the pollution source. The fluctuation of Cr(VI) concentration in the outflow of groundwater with salinity alteration during two-dimensional transport was different from that of the cations. The pollution plume of Cr formed by its two-dimensional migration was also obviously different from that of Ni(II). Therefore, when there was combined pollution of Cr(VI) and heavy metal cations, environmental management strategies and remediation strategies should be carefully proposed. |
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