Bizmark Navid, Schneider Joanna, Priestley Rodney D, Datta Sujit S
Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, NJ 08544, USA.
Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.
Sci Adv. 2020 Nov 13;6(46). doi: 10.1126/sciadv.abc2530. Print 2020 Nov.
Diverse processes-e.g., environmental pollution, groundwater remediation, oil recovery, filtration, and drug delivery-involve the transport of colloidal particles in porous media. Using confocal microscopy, we directly visualize this process in situ and thereby identify the fundamental mechanisms by which particles are distributed throughout a medium. At high injection pressures, hydrodynamic stresses cause particles to be continually deposited on and eroded from the solid matrix-notably, forcing them to be distributed throughout the entire medium. By contrast, at low injection pressures, the relative influence of erosion is suppressed, causing particles to localize near the inlet of the medium. Unexpectedly, these macroscopic distribution behaviors depend on imposed pressure in similar ways for particles of different charges, although the pore-scale distribution of deposition is sensitive to particle charge. These results reveal how the multiscale interactions between fluid, particles, and the solid matrix control how colloids are distributed in a porous medium.
多种过程，例如环境污染、地下水修复、石油开采、过滤和药物输送，都涉及到胶体颗粒在多孔介质中的传输。利用共聚焦显微镜，我们直接在原位可视化这一过程，从而确定颗粒在整个介质中分布的基本机制。在高注入压力下，流体动力应力导致颗粒不断沉积在固体基质上并从其上侵蚀下来——值得注意的是，迫使它们分布在整个介质中。相比之下，在低注入压力下，侵蚀的相对影响受到抑制，导致颗粒聚集在介质入口附近。出乎意料的是，尽管沉积的孔隙尺度分布对颗粒电荷敏感，但对于不同电荷的颗粒，这些宏观分布行为以类似的方式取决于施加的压力。这些结果揭示了流体、颗粒和固体基质之间的多尺度相互作用如何控制胶体在多孔介质中的分布。
