Pavel Hrabánek

Incorporation of zeolites in polyimide matrices

3-Aminopropyltriethoxysilane terminated polyimide precursors (polyamic acids) and Silicalite-1 were used to prepare zeolite-filled polyimide films. The accessibility of the pores of the zeolite built in both non-treated and treated polyimide matrices was studied using sorption of iodine from the vapour phase. Transport properties of the filled films were investigated using small probe molecules of hydrogen and methane.

Long-term stability of composite zeolite MFI membranes

Zeolite MFI layers were grown on asymmetric α-alumina supports developed in cooperation with an industrial partner. The layers were prepared by direct hydrothermal synthesis procedure using aged synthesis solutions composed of silica source, structure directing agent and deionized water. Selected zeolite MFI composite membranes were tested during long-term permeation and separation experiments to determine flux and separation factor as a function of total molar amount fed to zeolite membrane surface area. The flux of permeating components (n-butane, isobutane) was reduced by an average factor of 1.6 and 2 for n-butane and isobutane, respectively after 30 mol of butane isomers passed the selected membranes. The separation factor towards n-butane showed the maximum or decreased with increasing feeding amount of butane isomers.

Mathematical modelling of multicomponent transport in composite all-ceramic membranes containing a zeolitic phase

Abstract The membrane model describes (i) mass transport in macroporous support comprising diffusion in transition region between Knudsen and bulk diffusion superimposed on convective flow and (ii) mass transport in zeolitic phase accompanied by a parallel transport in defects of zeolitic layer. The mass transport in the support is described by Dusty Gas Model (DGM) and that in the zeolitic phase by Generalized Maxwell Stefan (GMS) approach. Parallel transport in defects of zeolitic layer is also described by DGM. Modelling is exemplified on dynamics of a semi-open Wicke-Kallenbach (W-K) cell operated with a flat silicalite-1-α-Al2O3 membrane using a CH4/N2 mixture. It appeared that measurement of dynamic responses of the semi-open W-K cell represents a rapid and precise method to characterize composite membrane quality.