Importance of boundary effects in diffusion of hydrocarbon molecules in a one-dimensional zeolite channel

TL;DR

This paper investigates how boundary effects influence the diffusion of hydrocarbon molecules in one-dimensional zeolite channels, combining experimental data, analytical modeling, and Monte Carlo simulations to understand single-file diffusion dynamics.

Contribution

It provides an analytical description of single-file hydrocarbon diffusion in zeolites, highlighting the significance of boundary desorption energies and mutual blockage effects.

Findings

Boundary desorption energy affects diffusion temperature.

Analytical model agrees with experimental data.

Mutual blockage impacts two-component diffusion.

Abstract

Single-file diffusion of propane and toluene molecules inside a narrow, effectively one-dimensional zeolite pore was experimentally studied by Czaplewski {\sl et al.} Using a stochastic lattice gas approach, we obtain an analytical description of this process for the case of single-component loading. We show that a good quantitative agreement with the experimental data for the desorption temperature of the hydrocarbon molecules can be obtained if the desorption process from the boundary is associated with a higher activation energy than the diffusion process in the bulk. We also present Dynamical Monte Carlo simulation results for two-component loading which demonstrate in agreement with the experimental findings the effects of mutual blockage of the molecules due to single-file diffusion.