Model for Predicting Adsorption Isotherms and the Kinetics of Adsorption via Steepest-Entropy-Ascent Quantum Thermodynamics

TL;DR

This paper introduces a first-principles quantum thermodynamic framework, SEAQT, to predict non-equilibrium adsorption processes and kinetics, validated against experimental data, without prior knowledge of specific mechanisms.

Contribution

It develops a novel SEAQT-based model for multi-component adsorption, capable of predicting adsorption paths and properties out of equilibrium without prior mechanistic assumptions.

Findings

Good agreement with experimental data

Effective description of non-equilibrium adsorption

Thermodynamic properties characterized by fluctuations

Abstract

This work outlines the foundations for being able to do a first-principle study of the adsorption process using the steepest-entropy-ascent quantum thermodynamic (SEAQT) framework, a framework able to predict the unique non-equilibrium path taken by a system from some initial state to stable equilibrium. To account for the process of multi-component adsorption, the SEAQT framework incorporates the particle number operator for each absorbed species directly into its equation of motion. The theoretical models developed are validated via some initial comparisons with experimental data found in the literature, demonstrating good agreement. The findings reveal that this framework can be an effective tool for describing the adsorption process out of equilibrium. It is able to do so without $a \; priori$ knowledge of the specific adsorption mechanism(s) involved. It also aligns well with the anticipated predictions of equilibrium models. In addition, within this framework, all intensive thermodynamic properties are characterized by out-of-equilibrium fluctuations, highlighting the significance of non-equilibrium thermodynamics in predicting measurable physical quantities.