Kinetics and thermodynamics across single-file pores: solute permeability and rectified osmosis

TL;DR

This paper models the impact of solute interactions on osmotic transport through single-file pores, providing insights into permeability and rectified osmosis with applications to biomembranes and zeolites.

Contribution

It extends kinetic models to include solute entry into pores, linking microscopic parameters to osmotic flux reduction and proposing new experimental approaches.

Findings

Solute-pore interactions reduce solvent flow, modeled by Langmuir isotherm.

Reflection coefficients are derived from microscopic kinetic parameters.

The model applies to water transport in biomembranes and particle movement in zeolites.

Abstract

We study the effects of solute interactions on osmotic transport through pores. By extending single-file, single-species kinetic models to include entrance of solute into membrane pores, we model the statistical mechanics of competitive transport of two species across membrane pores. The results have direct applications to water transport across biomembrane pores and particle movement in zeolites, and can be extended to study ion channel transport. Reflection coefficients, the reduction of osmotic fluxes measured using different solutes, are computed in terms of the microscopic kinetic parameters. We find that a reduction in solvent flow due to solute-pore interactions can be modelled by a Langmuir adsorption isotherm. Osmosis experiments are discussed and proposed. Special cases and Onsager relations are presented in the Appendices.