Mesoscale Simulations Reveal How Salt Influences Clay Particles Agglomeration in Aqueous Dispersions

Area of Science:

• Colloid and Surface Science
• Computational Materials Science
• Environmental Engineering

Background:

• Clay particle aggregation is a complex, multiscale phenomenon vital to scientific and industrial processes.
• Understanding particle-solvent and particle-particle interactions is key to controlling aggregation.
• Existing models often lack the multiscale detail to fully capture aggregation mechanisms.

Purpose of the Study:

• To develop a multiscale computational approach for understanding and controlling clay particle aggregation.
• To investigate the influence of salt concentration on clay aggregation mechanisms.
• To provide a simulation protocol applicable to preventing pore blocking in porous media.

Main Methods:

• Utilized molecular simulations at atomic resolution to compute potential of mean force (PMF) profiles.
• Employed molecular dynamics simulations at the mesoscale in implicit solvents.
• Quantified aggregate size and shape under varying system conditions, including salt concentration.

Main Results:

• Demonstrated that salt concentration significantly affects the potential of mean force between kaolinite particles.
• Observed that particle agglomeration in pure water results in large aggregates.
• Found that the presence of sodium chloride leads to numerous small aggregates, consistent with experimental data.

Conclusions:

• The developed multiscale simulation approach provides fundamental insights into clay aggregation mechanisms.
• Salt concentration plays a critical role in determining the size and number of clay aggregates.
• The simulation protocol shows potential for practical applications, such as preventing pore blocking in heterogeneous porous matrices.