Analytical evaluation of steady-state solute distribution in through-diffusion and membrane behavior test under non-perfectly flushing boundary conditions
Analytical evaluation of steady-state solute distribution in through-diffusion and membrane behavior test under non-perfectly flushing boundary conditions
复制标题
DOI：
10.1016/j.jrmge.2023.04.010
复制
发表时间：
2023-06
影响因子：
7.3
通讯作者：
G. Chen;Yuchao Li;K. Sample-Lord;Shan Tong
中科院分区：
文献类型：
--
作者：
G. Chen;Yuchao Li;K. Sample-Lord;Shan Tong
利用闭合系统装置的渗透扩散和膜性能测试程序已广泛用于同时测量低渗透粘土基屏障材料的扩散系数和膜效率系数。然而，样品边界完全冲洗条件的普遍假设可能会在扩散系数和膜效率的分析中引起误差。在这项研究中，提出了一种创新的准三维(3D)分析方法来评估土壤-多孔圆盘系统界面上的溶质分布，考虑了非完全冲洗条件。在考虑不同流入/流出位置的两种情景下，计算结果与数值模型基本一致。结果表明，该模型是一种准确、可靠的计算溶质沿边界分布的方法。基于该分析方法计算的膜效率系数和扩散系数更加准确，相对误差比采用进、出水浓度算术平均值的传统方法小50%。粘土试件的延迟因子也可以用修正的累积质量法来计算。最后，模拟的瞬时溶质运移与多级贯通扩散和膜行为试验的实验数据相吻合，验证了该方法的准确性。
The through-diffusion and membrane behavior testing procedure using a closed-system apparatus has been widely used for concurrent measurement of diffusion and membrane efficiency coefficients of low-permeability clay-based barrier materials. However, the common assumption of perfectly flushing conditions at the specimen boundaries could induce errors in analyses of the diffusion coefficients and membrane efficiencies. In this study, an innovative pseudo three-dimensional (3D) analytical method was proposed to evaluate solute distribution along the boundary surfaces of the soil-porous disks system, considering the non-perfectly flushing conditions. The results were consistent with numerical models under two scenarios considering different inflow/outflow positions. The proposed model has been demonstrated to be an accurate and reliable method to estimate solute distributions along the boundaries. The calculated membrane efficiency coefficient and diffusion coefficient based on the proposed analytical method are more accurate, resulting in up to 50% less relative error than the traditional approach that adopts the arithmetic mean value of the influent and effluent concentrations. The retardation factor of the clay specimen also can be calculated with a revised cumulative mass approach. Finally, the simulated transient solute transport matched with experimental data from a multi-stage through-diffusion and membrane behavior test, validating the accuracy of the proposed method.