Relating mechanistic fate with spatial positioning for colloid transport in surface heterogeneous porous media
Relating mechanistic fate with spatial positioning for colloid transport in surface heterogeneous porous media
复制标题
将表面非均质多孔介质中胶体传输的机械命运与空间定位联系起来
DOI：
10.1016/j.jcis.2023.03.005
复制
发表时间：
2023
影响因子：
9.9
通讯作者：
Morales, Verónica L.
中科院分区：
文献类型：
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作者：
Patiño, Janis E.;Johnson, William P.;Morales, Verónica L.
假设：胶体在地下多孔介质中的传输行为受到表面化学和物理非均质性的影响。了解所涉及的机制和分布结果对于评估和控制地下水污染至关重要。实验/模型：利用X射线微电子计算机层析成像获得的银粒子沿玻璃微珠填充柱的空间分布和机械放大模型研究了胶体在界面尺度、捕集器尺度、孔道尺度和达西尺度上的滞留。模拟的能量分布考虑了可变的胶体-颗粒相互作用，用于通过全力-力矩平衡从粒子轨迹确定收集器效率。我们的结果表明：(I)在表面非均质性的情况下，单个胶体-颗粒相互作用是非唯一的，并且跨越从排斥到吸引的极端；(Ii)实验观察到的颗粒-水界面和颗粒-颗粒接触处的滞留的空间位置分别由机械附着在颗粒表面和在后流滞留区的非接触滞留所控制；以及(Iii)实验观察到的非单调的滞留剖面和重尾的穿透曲线可以通过在较小尺度上显式实施非均质性来模拟。
Hypotheses:The transport behavior of colloids in subsurface porous media is altered by surface chemical and physical heterogeneities. Understanding the mechanisms involved and distribution outcomes is crucial to assess and control groundwater contamination. The multi-scale processes that broaden residence time distribution for particles in the medium are here succinctly described with an upscaling model.Experiments/model:The spatial distribution of silver particles along glass bead-packed columns obtained from X-ray micro-computed tomography and a mechanistic upscaling model were used to study colloid retention across interface-, collector-, pore-, and Darcy-scales. Simulated energy profiles considering variable colloid-grain interactions were used to determine collector efficiencies from particle trajectories via full force-torque balance. Rate coefficients were determined from collector efficiencies to parameterize the advective–dispersive-reactive model that reports breakthrough curves and depth profiles.Findings:Our results indicate that: (i) with surface heterogeneity, individual colloid-grain interactions are non-unique and span from repulsive to attractive extremes; (ii) experimentally observed spatial positioning of retention at grain-water interfaces and grain-to-grain contacts is governed respectively by mechanistic attachment to the grain surface and retention without contact at rear-flow stagnation zones, and (iii) experimentally observed non-monotonic retention profiles and heavy-tailed breakthrough curves can be modeled with explicit implementation of heterogeneity at smaller scales.