This paper presents an experimental and numerical investigation of the electrokinetic propagation of acid or base fronts through clayey soil. The experimental study included measuring the electric current, the mass of water extracted, and the advance of the acid and base fronts in synthetic sediment composed of 25% kaolinite and 75% silt. The results show that the flux rate remains constant over time and that the medium acidifies with time. The numerical model is based on the transport equations and, by considering adsorption and auto-ionization of water, it describes the temporal evolution of pH in the specimen. The experimental evaluation of the adsorption isotherms allows us to calculate the retardation factor, which is 69 and 19.5 for the hydronium and hydroxyl ions, respectively. Given these retardation factors, the results of the numerical model are consistent with experimental results and show how the acid and base fronts evolve in a saturated porous medium. Numerical model results show that electromigration is the major contributor to the migration of ions in the porous medium during electrokinetic treatment.

中文翻译：

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粘土中酸和碱前沿的电动传播：实验和数值研究

本文介绍了酸或碱前沿通过黏性土壤的电动传播的实验和数值研究。实验研究包括测量电流、提取的水质量以及由 25% 高岭石和 75% 淤泥组成的合成沉积物中酸和碱前沿的推进。结果表明，通量率随时间保持恒定并且介质随时间酸化。数值模型基于传输方程，通过考虑水的吸附和自电离，它描述了样品中 pH 值的时间演变。吸附等温线的实验评估使我们能够计算阻滞因子，水合氢离子和氢氧根离子分别为 69 和 19.5。鉴于这些延迟因素，数值模型的结果与实验结果一致，显示了酸和碱前沿如何在饱和多孔介质中演化。数值模型结果表明，电迁移是电动处理过程中多孔介质中离子迁移的主要原因。