Electroosmotic flow and Joule heating in preparative continuous annular electrochromatography

Area of Science:

• Analytical Chemistry
• Chemical Engineering
• Computational Science

Background:

• Annular electrochromatography involves complex hydrodynamics and Joule heating.
• Understanding local interactions is crucial for optimizing separation processes.
• Electrical conductivity changes due to ion migration significantly influence heat generation.

Purpose of the Study:

• To develop and validate a computational fluid dynamic (CFD) model for annular electrochromatography.
• To investigate the interplay between hydrodynamics and Joule heating.
• To correlate simulated results with experimental data.

Main Methods:

• Developed a CFD model using openFOAM, incorporating Navier-Stokes, energy, and mass transfer equations.
• Embedded simulations within ANSYS Fluent and openFOAM environments.
• Utilized a C8 reverse-phase monolith stationary phase prepared via in situ sol-gel process.
• Employed thermal camera and gravimetric methods for experimental validation.

Main Results:

• The model accurately described local hydrodynamics and Joule heating effects.
• Simulations showed that electrokinetic ion migration causes localized conductivity declines and increased Joule heat.
• Experimental and simulated values for temperature and hydrodynamics showed good agreement.

Conclusions:

• The developed CFD model provides a reliable tool for analyzing electrochromatography systems.
• Joule heating significantly impacts local conditions within the annular gap.
• The study demonstrates successful integration of simulation and experimental validation for chromatography optimization.