For reactive transport process in porous media, limited mixing and non-Fickian behavior are difficult to understand and predict. To explore the effects of anomalous diffusion and limited mixing, the column-based experiments of bimolecular reactive migration were performed and simulated by the CTRW-FEM model (continuous time random walk-finite element method). Simulated parameters were calibrated and the correlation coefficients between modeled and observed BTCs (breakthrough curves) were greater than 0.9, indicating that CTRW-FEM can solve over-prediction and tailing problems effectively. Porous media with coarser particle size show enhanced mixing and the non-Fickian behavior is not affected by particle size. β (a parameter of CTRW-FEM) and Da (Damkohler number) of CTRW-FEM under different Pe (Peclet number) values showed logarithmic linear relationship. Model sensitivity analysis of the CTRW-FEM model show that the peak concentration is most sensitive to the average pore velocity and the arriving peak time of peak concentration is most sensitive to β. These findings provide a theoretical basis for handling mixing and non-Fickian behavior patterns under actual environmental conditions.

中文翻译：

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多孔介质中的双分子反应输运实验和模拟

对于多孔介质中的反应输运过程，有限的混合和非 Fickian 行为难以理解和预测。为了探索异常扩散和有限混合的影响，通过 CTRW-FEM 模型（连续时间随机游走有限元方法）进行了基于柱的双分子反应迁移实验并进行了模拟。对模拟参数进行了校准，模拟和观察到的BTC（突破曲线）之间的相关系数大于0.9，表明CTRW-FEM可以有效解决过度预测和拖尾问题。具有较粗颗粒尺寸的多孔介质显示出增强的混合，并且非菲克行为不受颗粒尺寸的影响。CTRW-FEM的β（CTRW-FEM的一个参数）和Da（Damkohler数）在不同Pe（佩克莱特数）值下呈对数线性关系。CTRW-FEM模型的模型敏感性分析表明，峰值浓度对平均孔隙速度最敏感，峰值浓度到达峰值时间对β最敏感。这些发现为在实际环境条件下处理混合和非 Fickian 行为模式提供了理论基础。