Simulation of structural and permeation properties of multi-layer ceramic membranes

Abstract

In the present work we describe and use a reconstruction technique for the pore structure characterization of ceramic membranes, aiming to give a deeper view on the relation between structural and permeation properties of these materials. For this purpose, we have considered multi-layer asymmetric α-Al 2O 3 membranes that are commercially used in micro- and ultrafiltration applications. Subsequently, we employ stochastic techniques to generate three-dimensional reconstructions, for each membrane layer, that share the basic structural properties of the original materials determined directly from SEM studies. The viscous flow permeability of each layer is estimated by solving numerically the momentum equation in the void space of the reconstructed media. In addition, the Knudsen permeability is predicted through a Monte Carlo random walk simulation technique. The very good agreement between predicted and experimentally measured permeability values, without the need to resort to any fitting parameter, renders the proposed reconstruction methodology quite promising for reliable characterization and representation of the pore structure of this type of membrane.