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Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers
Published on: October 17, 2013
Colloid transport in dual-permeability media
Feike J Leij1, Scott A Bradford
1Dept. of Civil Engineering and Construction Engineering Management, California State University, 1250 Bellflower Boulevard - MS5101, VEC-206, Long Beach, CA 90840-5101, USA. Feike.Leij@csulb.edu
Journal of Contaminant Hydrology
|May 17, 2013
Summary
Colloid transport in structured porous media is faster due to preferential pathways. A new model accurately describes colloid movement and retention in dual-permeability systems, aiding contaminant risk assessment.
Area of Science:
- Environmental Science
- Geosciences
- Hydrogeology
Background:
- Colloids travel faster and farther in natural porous media than in lab settings.
- Preferential pathways in subsurface environments increase risks from contaminants and microorganisms.
- Understanding colloid transport is crucial for assessing environmental risks.
Purpose of the Study:
- To develop and validate a model for colloid transport in dual-permeability media.
- To investigate the effects of reversible and irreversible colloid retention.
- To analyze colloid transport in a composite porous medium with distinct sand grain sizes.
Main Methods:
- Developed an analytical model for colloid transport incorporating dual-permeability, reversible/irreversible retention, and inter-phase exchange.
- Utilized Laplace transformation and matrix decomposition to derive analytical solutions.
- Experimentally validated the model using a bromide tracer and 1-μm and 3.2-μm colloids in a composite sand medium.
Main Results:
- The model accurately described bromide tracer transport and estimated pore-water velocities.
- Most colloid breakthrough curves were well-described by the model.
- Larger colloids (3.2-μm) showed greater dispersivity and retention; finer sands exhibited higher retention rates.
Conclusions:
- The developed analytical model effectively simulates colloid transport in dual-permeability media.
- Model parameters provide insights into colloid behavior, including size-dependent retention and dispersivity.
- Further research is needed to confirm transport parameters due to sample size and flow complexity.
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