Direct microscopic observation of particle deposition in porous media: Role of the secondary energy minimum
Direct microscopic observation of particle deposition in porous media: Role of the secondary energy minimum
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DOI：
10.1016/j.colsurfa.2006.08.007
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发表时间：
2007-02-15
影响因子：
5.2
通讯作者：
Elimelech, Menachem
中科院分区：
文献类型：
--
作者：
Kuznar, Zachary A.;Elimelech, Menachem
已构建了一个流动池，其中微米大小的颗粒水平流过单层填充的玻璃珠。通过具有相差功能的荧光显微镜观察沉积。这样可以实时可视化多孔介质中的颗粒沉积，并深入了解物理化学过滤过程中颗粒和微生物病原体的二次最小沉积等现象。在低离子强度 (1-3 mM) 下，在收集珠上未观察到沉积。当一价盐浓度升高到中等离子强度 (10-30 nnM) 时，颗粒被捕获在次要最小值中并沿着玻璃珠表面平移，在球形收集器的后部附近聚集。在高离子强度 (100 mM) 下，不存在计算得出的沉积静电能垒，颗粒沉积在球形收集器的整个表面上。结论是，二次能量最小值处的沉积是流经粒状多孔介质时微米级颗粒的重要去除机制。 (c) 2006 Elsevier B.V. 保留所有权利。
A flow-cell has been constructed where micrometer-sized particles flow horizontally through a single layer of packed glass beads. Deposition is viewed through a fluorescent microscope with phase contrast capabilities. This allows the visualization of particle deposition in porous media in real time and provides insight into phenomena such as secondary minimum deposition of particles and microbial pathogens during physicochemical filtration. At low ionic strengths (1-3 mM), no deposition was observed on the collector beads. As the monovalent salt concentration was raised to moderate ionic strengths (10-30 nnM), the particles became trapped in the secondary minimum and translated along the glass bead surface, accumulating near the rear of the spherical collectors. At high ionic strength (100 mM), no calculated electrostatic energy barrier to deposition exists and particles deposited over the entire surface of the spherical collector. It is concluded that deposition in the secondary energy minimum is an important removal mechanism for micrometer-sized particles in flow through granular porous media. (c) 2006 Elsevier B.V. All rights reserved.