Charge regulated solid-liquid interfaces interacting on the nanoscale: Benchmarking of a generalized speciation code...

Area of Science:

• Colloid and Surface Science
• Environmental Chemistry
• Materials Science

Background:

• Surface chemistry dictates electrostatic forces in aqueous particle interactions.
• Existing models often neglect dynamic changes in surface and solution speciation during particle approach.
• Accurate modeling of these interactions is crucial for understanding colloidal behavior.

Purpose of the Study:

• To advance charge regulation calculations by incorporating full chemical speciation.
• To develop a coupled model integrating surface complexation and Poisson-Boltzmann distributions for inter-particle forces.
• To enhance the accuracy of electrostatic interaction calculations, especially at small separations.

Main Methods:

• Coupling advanced surface complexation models (e.g., Basic Stern, three-, four-plane) with Poisson-Boltzmann equation for inter-particle space.
• Implementing numerical solutions for arbitrary electrolytes and various geometries.
• Developing and validating a Python-based code and COMSOL implementation against benchmark cases.

Main Results:

• Demonstrated improved accuracy in inter-particle force calculations compared to constant charge/potential models.
• Validated the developed codes through benchmark calculations against established speciation codes.
• Showcased the flexibility and precision of the new modeling approach for diverse chemical conditions.

Conclusions:

• The developed charge regulation models offer a more accurate quantification of electrostatic interactions by accounting for speciation changes.
• The implemented codes provide a versatile tool for analyzing a wide range of systems, including industrial, biological, and environmental applications.
• This work opens new avenues for studying nano-confined systems and complex colloidal phenomena.