Attachment and detachment rate distributions in deep-bed filtration

Area of Science:

• Colloid and surface science
• Porous media physics
• Environmental engineering

Background:

• Colloid transport in saturated porous media is crucial for understanding contaminant fate and transport.
• Traditional models often simplify attachment-detachment processes, limiting their predictive power under unfavorable conditions.
• Physical straining and hydrodynamic dispersion significantly influence colloid deposition dynamics.

Purpose of the Study:

• To develop a novel mean-field model for colloid transport and deposition in porous media.
• To analytically investigate the model's behavior, including filtering front dynamics.
• To propose an experimental method for model parameterization.

Main Methods:

• A mean-field approach characterizing attachment and detachment with a spectrum of rate constants.
• Analytical solution to derive long-time asymptotic behavior and deposition profiles.
• Examination of filtering front structure, stability, and propagation velocity.

Main Results:

• The model captures a spectrum of trapping sites, from reversible to permanent.
• An analytical solution reveals insights into deposition curve profiles and asymptotic behavior.
• The filtering front's characteristics (structure, stability, velocity) are elucidated.

Conclusions:

• The proposed mean-field model provides an effective analytical framework for colloid transport and deposition.
• The model accurately describes phenomena influenced by both hydrodynamic dispersivity and physical straining.
• An experimental protocol is suggested for precise model parameter determination.