Testing the Validity of the Miscible-Displacement Interfacial Tracer Method for Measuring Air-Water Interfacial Area: Independent Benchmarking and Mathematical Modeling.
Testing the Validity of the Miscible-Displacement Interfacial Tracer Method for Measuring Air-Water Interfacial Area: Independent Benchmarking and Mathematical Modeling.
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DOI：
10.1016/j.chemosphere.2020.128193
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发表时间：
2021-01
期刊：
影响因子：
8.8
通讯作者：
Brusseau ML
中科院分区：
文献类型：
--
作者：
El Ouni A;Guo B;Zhong H;Brusseau ML
通过水相混驱柱实验进行的界面示踪试验（ITT）是测量多孔介质空气-水界面面积的几种方法之一。本研究的主要目的是检验用界面示踪剂试验获得的空气-水界面面积测量结果的稳健性，并检验该方法的总体有效性。研究了表面活性剂诱导流动的潜在发生和影响，并进行了测量复制。在测试期间称量柱和流出样品，以监测水饱和度和通量的潜在变化。在使用真空室系统维持稳定流动条件的实验中，观察到水饱和度和通量的最小变化。用混相驱替法测量的空气-水界面面积与不受表面活性剂诱导流动影响的方法测量的界面面积完全匹配。在所有三种被测试的介质和饱和度范围内，都观察到这种成功的基准测试。建立了表面活性剂在固-水和空气-水界面上的非线性和限速吸附以及表面张力变化对基质电位和流动的影响的数学模型来模拟示踪剂试验。独立预测的模拟结果与实测数据非常吻合，表明真空系统的使用最大限度地减少了表面活性剂引起的流动及其相关影响。这些结果完全明确地表明，在现有条件下，混相置换ITT方法可以准确可靠地测量空气-水界面面积。
The interfacial tracer test (ITT) conducted via aqueous miscible-displacement column experiments is one of a few methods available to measure air-water interfacial areas for porous media. The primary objective of this study was to examine the robustness of air-water interfacial area measurements obtained with interfacial tracer tests, and to examine the overall validity of the method. The potential occurrence and impact of surfactant-induced flow was investigated, as was measurement replication. The column and the effluent samples were weighed during the tests to monitor for potential changes in water saturation and flux. Minimal changes in water saturation and flux were observed for experiments wherein steady flow conditions were maintained using a vacuum-chamber system. The air-water interfacial areas measured with the miscible-displacement method completely matched interfacial areas measured with methods that are not influenced by surfactant-induced flow. This successful benchmarking was observed for all three media tested, and over a range of saturations. A mathematical model explicitly accounting for nonlinear and rate-limited adsorption of surfactant at the solid-water and air-water interfaces as well as the influence of changes in surface tension on matric potentials and flow was used to simulate the tracer tests. The independently-predicted simulations provided excellent matches to the measured data, and revealed that the use of the vacuum system minimized the occurrence of surfactant-induced flow and its associated effects. These results in total unequivocally demonstrate that the miscible-displacement ITT method produced accurate and robust measurements of air-water interfacial area under the extant conditions.