Theoretical Investigation of the Nonlinear General Rate Model with the Bi-Langmuir Adsorption Isotherm Using...

Area of Science:

• Chemical Engineering
• Separation Science
• Computational Modeling

Background:

• Core-shell particles offer enhanced separation efficiency in chromatography due to optimized diffusion pathways.
• Heterogeneous porous media require accurate models for solute transport, often involving nonlinear adsorption isotherms like the bi-Langmuir model.
• Efficient separation of complex mixtures is crucial in various chemical and pharmaceutical processes.

Purpose of the Study:

• To numerically approximate a nonlinear isothermal general rate model for stationary bed columns with core-shell adsorbents.
• To investigate the impact of intraparticle diffusion, film mass resistance, axial dispersion, and core radius on separation performance.
• To determine the optimal core radius fraction for maximizing separation efficiency.

Main Methods:

• Implementation of a second-order, semidiscrete, high-resolution finite volume method.
• Simulation of single solute and multi-component mixture flows through a theoretical model.
• Analysis of elution curves under varying physical and operational parameters.

Main Results:

• The study theoretically illustrates the effects of diffusion, mass transfer resistance, and axial dispersion on simulated elution curves.
• A decrease in accessible pore volume and diffusion path length in porous shells leads to improved separation efficiency.
• The research identifies a range of optimal core radius fractions for enhanced separation performance.

Conclusions:

• The developed finite volume method accurately simulates solute transport in core-shell particles with double adsorption sites.
• Optimizing the core-shell particle design, specifically the core radius, is critical for achieving high-efficiency separations.
• This work provides a framework for designing advanced chromatographic materials and processes.