Extracting surface diffusion coefficients from batch adsorption measurement data: application of the classic Langmuir...

Area of Science:

• Chemical Engineering
• Materials Science
• Physical Chemistry

Background:

• Estimating surface diffusion coefficients typically requires fitting numerical solutions of complex diffusion models to experimental data.
• Non-linear systems often necessitate computationally intensive numerical methods for accurate diffusion modeling.

Purpose of the Study:

• To present a simplified analytical method for determining surface diffusion coefficients using the Langmuir kinetics model.
• To reduce the computational complexity associated with extracting surface diffusion coefficients from batch kinetic data.

Main Methods:

• Applied the Langmuir kinetics model to batch kinetic data to derive an analytical expression for surface diffusion coefficients.
• Determined the Langmuir rate coefficient as an intermediate step for calculating the surface diffusion coefficient.
• Validated the method by comparing results with those obtained from traditional surface diffusion models.

Main Results:

• Successfully extracted surface diffusion coefficients in the range of 10⁻⁹ to 10⁻⁶ cm²/s.
• Demonstrated consistency between coefficients obtained via the Langmuir kinetics model and conventional surface diffusion models.
• The Langmuir kinetics model provides an analytical, closed-form algebraic equation, simplifying parameter estimation.

Conclusions:

• The Langmuir kinetics model offers a computationally efficient alternative for estimating surface diffusion coefficients.
• This simplified approach reduces the need for complex numerical solutions in analyzing batch kinetic data.
• The method is suitable for applications requiring straightforward and rapid determination of surface diffusion properties.