Assessing mass transfer rates in porous adsorbents using gas adsorption microcalorimetry

Abstract

Abstract A novel method to estimate mass transfer kinetics in porous adsorbents using gas adsorption microcalorimetry is described. By fitting an appropriate model to experimental microcalorimetric peaks, both the LDF constant and the effective diffusion time constant could be estimated. Results are shown for an activated carbon and zeolite 13X. The experimental apparatus consisting of a microcalorimeter coupled to a controlled gas dosing system was described in the model by four control volumes: the dosing vessel, the dead volume, the measuring cell and the composite wall surrounding the cell. The proposed model was able to accurately describe the microcalorimetric peaks obtained upon each gas injection. The sensitivity of the model solution to the diffusion parameters was analyzed and adequate ranges of experimental conditions allowing for accurate parameter estimation could be determined. Mass transfer parameters found by this technique are in agreement with those reported in the literature by other experimental techniques.