Non-isothermal surface barrier model for gas sorption kinetics on porous adsorbents

Abstract

A review of the progressive development of the models for kinetics of adsorption is given and a new non-isothermal surface barrier model is proposed. The present model assumes that the adsorbate mass-transfer resistance is confined at the surface of the adsorbent particle and that heat transfer from the adsorbent mass is controlled by both its effective thermal conductivity and the external film heat-transfer resistance. Analytic equations are derived for describing adsorbate uptake and adsorbent temperature profiles.

The model successfully describes the adsorption of iso-octane on 13X, n-pentane on 5 Å and carbon dioxide on 4 Å zeolites using a set of self-consistent parameters. The internal and the external heat-transfer coefficients evaluated from the uptake data agree well with those calculated using available theories.