Self-Limited Accumulation of Colloids in Porous Media

Area of Science:

• Colloid and Surface Science
• Fluid Dynamics
• Materials Science

Background:

• Understanding particle transport in porous media is crucial for applications like water filtration and enhanced oil recovery.
• Direct imaging of colloidal particle adsorption dynamics within complex geometries remains challenging.

Purpose of the Study:

• To directly visualize and quantify the progressive adsorption of colloidal particles within a 3D model porous medium.
• To investigate the influence of interparticle electrostatic interactions on particle deposition regimes.
• To develop a predictive model for colloid accumulation dynamics.

Main Methods:

• Local direct imaging techniques were employed to observe particle deposition in real-time.
• Interparticle electrostatic interactions were systematically varied to study different deposition behaviors.
• A probability model was developed incorporating particle adsorption and drag energies to explain observed trends.

Main Results:

• A wide spectrum of deposition regimes was observed, ranging from single-layer surface deposition to multi-layer accumulation and system clogging.
• Colloid accumulation was identified as a self-limited process, reaching a stable deposited fraction.
• The deposited fraction is governed by a balance between particle interaction forces and the imposed flow rate.

Conclusions:

• The study provides direct experimental validation of theoretical models for particle transport and accumulation in porous media.
• The findings offer a deeper understanding of the mechanisms governing colloid deposition, crucial for optimizing filtration and flow processes.
• The developed probability model accurately predicts colloid accumulation trends based on fundamental physical parameters.