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Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures
Published on: May 20, 2014
Interfacial interactions and colloid retention under steady flows in a capillary channel
Volha Lazouskaya1, Yan Jin, Dani Or
1Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA.
Journal of Colloid and Interface Science
|August 26, 2006
Summary
Colloids accumulate at the air-water interface (AWI) in capillary channels, with flow conditions significantly impacting their retention. Surface properties like apparent surface viscosity and tension are key to understanding colloid transport in porous media.
Area of Science:
- Colloid and Surface Science
- Fluid Dynamics
- Porous Media Research
Background:
- Colloidal interactions at interfaces are crucial for understanding transport in porous media.
- The behavior of colloids at the air-water interface (AWI) and contact line under flow is complex and not fully understood.
Purpose of the Study:
- To investigate colloidal interfacial interactions in a capillary channel under varying chemical and flow conditions.
- To examine the effects of ionic strength and flow on colloid retention at the AWI and contact line.
- To elucidate the role of surface properties in pore-scale colloid transport.
Main Methods:
- Confocal microscopy was used to study 1.1 micrometer fluorescent latex microspheres.
- Static and dynamic (flow) experiments were conducted in a capillary channel.
- Modeling and dimensionless analysis were employed to analyze flow behavior.
Main Results:
- Colloids preferentially accumulated at the AWI, though bulk transport was observed.
- Ionic strength (1-100 mM) had a minor effect on accumulation, suggesting non-electrostatic forces are dominant.
- Flow conditions promoted colloid accumulation at the AWI due to its non-stress-free boundary effect.
- Contact line retention was significant, enhanced by hydrodynamic forces in flow experiments.
Conclusions:
- Apparent surface viscosity and surface tension play critical roles in pore-scale colloidal interfacial retention.
- Findings provide insights into colloid fate and transport in unsaturated porous media.
- Understanding these interfacial phenomena is essential for environmental and industrial applications.
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