Colloid transport in saturated porous media: Elimination of attachment efficiency in a new colloid transport model
Colloid transport in saturated porous media: Elimination of attachment efficiency in a new colloid transport model
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DOI：
10.1002/wrcr.20195
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发表时间：
2013-05
影响因子：
5.4
通讯作者：
L. Landkamer;R. Harvey;Timothy Scheibe;J. Ryan
中科院分区：
文献类型：
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作者：
L. Landkamer;R. Harvey;Timothy Scheibe;J. Ryan
介绍了一种胶体输运模型，该模型在概念上是简单的，但捕获胶体的运输和保留在饱和多孔介质中的基本特征时，胶体的保留是由次要的最小，因为静电屏障抑制大量沉积在小学最小。该模型是基于传统的胶体过滤理论（CFT），但消除了附着效率的经验概念。胶体沉积速率是直接从CFT计算的，假设所有预测的胶体被收集器拦截，至少会导致第二极小值的暂时沉积。此外，还介绍了基于胶体群体异质性的胶体再夹带新范例。为了实现这一点，初始胶体群体被分成两部分。一部分，由于理化特性（例如，尺寸和电荷），将总是在捕获后重新夹带在第二个最小值中。胶体的剩余部分，再次作为物理化学特性的结果，将被保留“不可逆”时，捕获的第二个最小值。假设分散系数可以从示踪剂行为中估计，该模型只有两个拟合参数：（1）在被第二极小值拦截时将被“不可逆地”保留的初始胶体种群的分数，以及（2）可逆保留的胶体离开第二极小值的速率。这两个参数与Derjaguin-朗道-Verwey-Overbeek（DLVO）二次能量最小值和孔隙水速度的深度相关，这两个物理力影响胶体运输。鉴于这种相关性，该模型作为一个启发式的工具，探索物理参数，如表面电位和流体速度对胶体运输的影响。
A colloid transport model is introduced that is conceptually simple yet captures the essential features of colloid transport and retention in saturated porous media when colloid retention is dominated by the secondary minimum because an electrostatic barrier inhibits substantial deposition in the primary minimum. This model is based on conventional colloid filtration theory (CFT) but eliminates the empirical concept of attachment efficiency. The colloid deposition rate is computed directly from CFT by assuming all predicted interceptions of colloids by collectors result in at least temporary deposition in the secondary minimum. Also, a new paradigm for colloid re‐entrainment based on colloid population heterogeneity is introduced. To accomplish this, the initial colloid population is divided into two fractions. One fraction, by virtue of physiochemical characteristics (e.g., size and charge), will always be re‐entrained after capture in a secondary minimum. The remaining fraction of colloids, again as a result of physiochemical characteristics, will be retained “irreversibly” when captured by a secondary minimum. Assuming the dispersion coefficient can be estimated from tracer behavior, this model has only two fitting parameters: (1) the fraction of the initial colloid population that will be retained “irreversibly” upon interception by a secondary minimum, and (2) the rate at which reversibly retained colloids leave the secondary minimum. These two parameters were correlated to the depth of the Derjaguin‐Landau‐Verwey‐Overbeek (DLVO) secondary energy minimum and pore‐water velocity, two physical forces that influence colloid transport. Given this correlation, the model serves as a heuristic tool for exploring the influence of physical parameters such as surface potential and fluid velocity on colloid transport.