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

Abstract

This study investigated the permeation behaviors of n-hexane and 2-methylpentane through two-types of silicalite-1 membranes that have different pore-connectivity. The permeation mechanisms of these hydrocarbons were able to be explained by the adsorption–diffusion model. In addition, the fluxes through silicalite-1 membranes could be expressed by the modified Fick’s first law. The hydrocarbon fluxes through S-1S with better pore-connectivity were ca. 3–20 times larger than those through S-1M with poor pore-connectivity. For these membranes with different pore-connectivity, the activation energy of diffusion of n-hexane was 17.5 kJ mol−1 for the membrane with better pore-connectivity and 18.0 kJ mol−1 for the membrane with poorer pore-connectivity, whereas for 2-methylpentane it was 17.9 and 33.0 kJ mol−1, respectively. We concluded that the pore-connectivity in silicalite-1 membrane significantly influences the molecular diffusivities.

Tailoring Nanochannel in ZSM-5 Membranes via Al Distribution Control

“…The activation energy of n -hexane permeation through silicalite-1 membrane, a kind of MFI-type zeolite without Al and cations in its framework, has been previously reported (18.0 kJ mol –1 ), which was remarkably similar to that through Na-ZSM-5 I membrane, indicating that Na + at the intersections hardly disturbs the permeation of n -hexane. In addition, the activation energies of n -hexane through H-ZSM-5 membranes were almost the same as those through the silicalite-1 membrane because the size of the proton was negligible.…”

“…We propose that the control of Al distribution can be a new horizon for the development of a zeolite membrane. Slight changes in pore size or adsorption properties greatly affect the permeation and separation properties of zeolite membranes. , Accordingly, controlling these factors via Al distribution can significantly improve the membrane performance. In this study, we developed ZSM-5 membranes with a controlled Al distribution for the first time.…”

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].…”