Interception Focusing of Colloid Transport in Granular Porous Media
Abstract
Colloid transport and retention in environmental granular porous media underlie groundwater resource protection from, and remediation using, biological and non-biological nano- and micro-particles (colloids). During transport, colloids periodically intercept grain surfaces and translate along them at separation distances across several tens of nm corresponding to the secondary minimum between the opposing forces of longer-range of van der Waals (VDW) attraction and shorter-range electric double layer (EDL) repulsion. Relatively weak diffusive translation of colloids supports their continued translation in secondary minimum association until they are expelled to bulk fluid at rear flow stagnation zones on grain leeward sides. We herein show that this dynamic focuses colloids into a network of fluid streamlines (incomplete mixing lamellae) that enhances their subsequent likelihood of interception with downgradient grains, i.e., increases the so-called collector efficiency (typically denoted by Greek letter eta). Interception focusing of colloids in granular porous media explains well-observed outcomes of colloid transport under environmental conditions, including nonmonotonic nonexponential profiles of retained colloids and the non-Markovian nature of extended tailing of low colloid concentrations following initial elution. Interception focusing is a fundamental process that distinguishes colloids from solutes and renders inapplicable to colloids the assumption that is often invoked for solutes of complete pore scale mixing in granular porous media.
Related
- Colloid recovery from porous structures under ambient flow: enhanced extraction via phoretic and osmotic mechanisms
- Spiral motion enables simultaneous homogenization and enhanced transport in granular pipe flow
- Amplified transport variability in granular slope flows near the critical angle
- Synchronization-controlled transport near an absorbing transition: Effective Enskog kinetic theory of a driven granular monolayer
- Interface Engineering of Porous Transport Layer‐Catalyst Layer in Proton Exchange Membrane Water Electrolyzers: A Comprehensive Review
BibTeX
@misc{johnson2026interception,
title = {{Interception Focusing of Colloid Transport in Granular Porous Media}},
author = {William P. Johnson and Noah G. Willis and Luis A. Ullauri and Bashar M. Al-Zghoul and Diogo Bolster},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.09947},
eprint = {2611.09947},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.09947},
}
RIS
TY - UNPB
TI - Interception Focusing of Colloid Transport in Granular Porous Media
AU - William P. Johnson
AU - Noah G. Willis
AU - Luis A. Ullauri
AU - Bashar M. Al-Zghoul
AU - Diogo Bolster
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.09947
UR - https://arxiv.org/abs/2611.09947
AB - Colloid transport and retention in environmental granular porous media underlie groundwater resource protection from, and remediation using, biological and non-biological nano- and micro-particles (colloids). During transport, colloids periodically intercept grain surfaces and translate along them at separation distances across several tens of nm corresponding to the secondary minimum between the opposing forces of longer-range of van der Waals (VDW) attraction and shorter-range electric double layer (EDL) repulsion. Relatively weak diffusive translation of colloids supports their continued translation in secondary minimum association until they are expelled to bulk fluid at rear flow stagnation zones on grain leeward sides. We herein show that this dynamic focuses colloids into a network of fluid streamlines (incomplete mixing lamellae) that enhances their subsequent likelihood of interception with downgradient grains, i.e., increases the so-called collector efficiency (typically denoted by Greek letter eta). Interception focusing of colloids in granular porous media explains well-observed outcomes of colloid transport under environmental conditions, including nonmonotonic nonexponential profiles of retained colloids and the non-Markovian nature of extended tailing of low colloid concentrations following initial elution. Interception focusing is a fundamental process that distinguishes colloids from solutes and renders inapplicable to colloids the assumption that is often invoked for solutes of complete pore scale mixing in granular porous media.
ER -