New insights into the ideal adsorbed solution theory

Area of Science:

• Physical Chemistry
• Materials Science
• Chemical Engineering

Background:

• Adsorption of gas mixtures on porous materials is crucial for separation processes.
• The Ideal Adsorbed Solution (IAS) theory is a common model for predicting mixture adsorption.
• Understanding deviations from IAS theory is essential for accurate process design.

Purpose of the Study:

• To simulate adsorption of CO2-CH4, CO2-N2, and CH4-N2 mixtures on porous carbon models.
• To validate and refine the application conditions of the IAS theory.
• To investigate the relationship between simulation data, experimental observations, and thermodynamic properties.

Main Methods:

• Grand Canonical Monte Carlo (GCMC) simulations were employed.
• Six different porous carbon models were utilized.
• Thermodynamic properties, including activity coefficients and chemical potentials, were calculated.

Main Results:

• Simulated data were shown to obey a newly formulated condition for IAS theory application.
• Deviations between IAS predictions and simulation results increased with pressure, mirroring experimental trends.
• Activity coefficients derived from simulations qualitatively and quantitatively matched experimental data.

Conclusions:

• The study provides a refined understanding of IAS theory applicability in gas mixture adsorption.
• It demonstrates a strong correlation between simulation results, experimental data, and thermodynamic behavior.
• New insights into the physical interpretation of activity coefficients and the relationship between chemical potentials and reduced temperature were presented.