(694a) Use of an Autosorb System for the Measurement of Diffusion of CO2 in an Ion-Exchanged Zeolite Rho

The Quantachrome Autosorb-iQ^™ is a state-of-the-art volumetric system for the measurement of BET surface areas, micropore volumes and adsorption isotherms of gases on solid adsorbents. It comes with a library of software tools which will interpret automatically the experimental results and yield the required equilibrium properties.

As part of the Adsorption Research Industrial Consortium at the University of Edinburgh, we are interested in expanding the use of commercial equipment to functionalities for which the systems can be used in a non-conventional way. We present the use of the Quantachrome Autosorb-iQ^™ for the measurement of diffusivities in a Zeolite Rho sample.

To interpret the dynamic response of the system we developed an analytical solution to a model which is adapted from the theoretical model developed by Brandani in 1998 for the analysis of the piezometric method. Due to the particular configuration of the instrument, modifications to this simplified model were applied in order to take account of the real experimental conditions. The results on carbon dioxide on Zeolite Rho, for which we have independent values measurements carried out using the ZLC technique, confirm the validity of the methodology in the analysis of slow diffusion processes.

We would like to acknowledge the financial support from the Engineering and Physical Sciences Research Council under grant EP/F034520/1 (Innovative Gas Separations for Carbon Capture) and M.M. Lozinska and P.A. Wright of the University of St. Andrews for providing the zeolite sample used in this study.