Pore-Scale Visualization of Colloid Transport and Retention in Partly Saturated Porous Media

By John T. Crist, J. McCarthy, Y. Zevi, Philippe C. Baveye, J. Throop, T. Steenhuis. 2004

136 citations recorded by the source corpus.

In unsaturated porous media, sorption of colloids at the air–water (AW) interface is accepted as a mechanism for controlling colloid retention and mobilization. However, limited actual pore-scale observations of colloid attachment to the AW interface have been made. To further investigate these processes, a real-time pore-scale visualization method was developed. The method builds on the light transmission technique for fingered flow studies in packed-sand infiltration chambers and combines it with high-resolution, electro-optical hardware and public domain imaging software. Infiltration and drainage of suspensions of hydrophilic negatively charged carboxylated latex microspheres provides compelling visual evidence that colloid retention in sandy porous media occurs via trapping in the thin film of water where the AW interface and the solid interface meet, the air–water–solid (AWS) interface. With this modified theory of trapped colloids at the AWS interface, we are able to explain the apparent discrepancy between previous experimental evidence of hydrophilic colloids seemingly partitioning to the AW interface and more recent findings that suggest this type of colloid does not adsorb at the AW interface.

Subfields: Environmental Engineering, Water Science and Technology

View Paper: https://www.semanticscholar.org/paper/b424952e8f6a18df61a2f8684d578ef80af456eb

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In Environmental Engineering

1. Jirka Šimůnek
2. S. Bradford
3. Sharon L Walker

In Water Science and Technology

1. Jirka Šimůnek
2. S. Bradford
3. Sharon L Walker

Citations in the corpus

• Significance of straining in colloid deposition: Evidence and implications (2006, background): “This research has provided valuable insight on colloid retention at the air-water interface and soil-air-water contact line [Wan and Wilson, 1994a; Sirivithayapakorn and Keller, 2003b; Crist et al., 2004; Wan and Tokunago, 2005; Steenhuis et al., 2005; Crist et al., 2005], colloid size exclusion [Si”
• Transport and Retention Mechanisms of Colloids in Partially Saturated Porous Media (2005, methodology): “Two pore volumesA similar experimental setup as Crist et al. (2004) was used of colloid-free solution of the same ionic strength and pH wereand includes an infiltration chamber, light source, electroapplied at the same application rate immediately following theoptical equipment (lens, camera, and…”