Contribution of Pore-Connectivity to Permeation Performance of Silicalite-1 Membrane; Part I, Pore Volume and Effective Pore Size

Abstract

The micropore volumes and effective pore sizes of two types of silicalite-1 membranes were compared with those of a typical silicalite-1 powder. The silicalite-1 membrane with fewer grain boundaries in the membrane layer showed similar micropore volume and effective pores size to those of the silicalite-1 powder. In contrast, when the silicalite-1 membrane contained many grain boundaries, relatively small micropore volume and effective pore size were observed, suggesting that narrowing and obstruction of the micropore would occur along grain boundaries due to the disconnection of the zeolite pore. The silicalite-1 membrane with fewer grain boundaries exhibited relatively high permeation properties for C6-C8 hydrocarbons. There was an over 50-fold difference in benzene permeance between these two types of membranes. We concluded that it is important to reduce grain boundaries and improve pore-connectivity to develop an effective preparation method for obtaining a highly permeable membrane.

Contribution of Pore-Connectivity to Permeation Performance of Silicalite-1 Membrane; Part II, Diffusivity of C6 Hydrocarbon in Micropore

“…We have focused our attention on grain boundaries that are formed by the collision of crystals in the course of the formation of the zeolite membrane. In part I, we prepared two types of silicalite-1 membranes and carefully investigated the microstructures of these membranes by using nano-permporometry, adsorption tests and permeation tests [13]. As a result, we concluded that the micropore volumes and effective pore size were strongly influenced by the existence of grain boundaries across the direction of molecular permeation.…”

“…In this study, the permeation properties of C 6 hydrocarbons were evaluated circumstantially in wide ranges of membrane temperatures and partial pressures. The two types of silicalite-1 membranes that have pore-connectivity of 60 and 47% were used for comparison [13]. The permeation properties were analyzed based on the adsorption-diffusion model, in order to discuss the effect of pore-connectivity on the diffusivity of hydrocarbons in the silicalite-1 membranes.…”

Effects of pore connectivity and tortuosity on the dynamics of fluids confined in sub-nanometer pores

“…13 This variation in the degree of interconnectivity of pore spaces may affect the behavior of fluids confined in them. [14][15][16][17][18] While fluid structure and dynamics under nano-confinement has been studied widely, studies addressing the effects of pore connectivity on fluid behavior under confinement are mostly limited to experimental 15,16 or theoretical 17,18 studies that lack molecular details.…”

Effects of Pore Connectivity on the Sorption of Fluids in Nanoporous Material: Ethane and CO2 Sorption in Silicalite

“…Another factor that gives rise to deviation from the ideal nanopore structure often used in computer simulations is the variable degree of inter-connectivity of pores [15][16][17].…”