Prof. William P. Johnston
Department of Civil and Environmental Engineering, Case Western Reserve University
Abstract: The field scale transport and spatial distribution of colloids (e.g., pathogens, clays, nanomaterials, nanoplastics, microplastics) in groundwater and other saturated porous media is dependent on nanoscale interactions with surfaces and pore-scale forces such as fluid drag, diffusion, and gravity. This talk describes how these nanoscale interactions and pore scale forces/torques impact transport at larger scales from packed columns to field settings. We will explore the role of nanoscale surface charge heterogeneity in explaining experimental observations regarding colloid transport in groundwater including: a) their attachment to like-charged surfaces; i.e., attachment under unfavorable conditions as is typical of environmental settings; and b) the recent finding that the gap between attachment to favorable (opposite-charged) surfaces versus unfavorable (like-charged) surfaces is maximal for colloids in the size range corresponding to the nano- to micro- transition (200 nm to 2 mm). This talk will explore the upscaling of pore scale transport behaviors to produce rate coefficients that describe or predict continuum-scale transport behaviors, with special attention to how this can be done under unfavorable transport conditions. A secondary objective of this talk is to introduce researchers to numerical modeling freeware (Parti-Suite) by which they can mechanistically simulate the multiscale colloid transport processes operating across nano-, pore-, and continuum scales.
Host：Prof. Cheng Gu
Executive Editor
Nanjing University
Time：09:00am August 15, 2022 (Beijing time)
Zoom ID: 816 9975 7155
Bilibili: 25002335
