Analysis of transient permeation fluxes into and out of membranes for adsorption measurements

Hydrogen separation from reforming gas using organic templating silica/alumina composite membrane

“…The temperature dependency of surface diffusivity can be expressed by the following Arrhenius-type relationship [12,15]:…”

Enhanced flux through double-sided zeolite membranes

“…Transport through the support was modeled allowing for contributions of Knudsen and molecular diffusion and viscous flow, as described previously [4,7,[13][14][15]. Which mechanism dominates depends on the support properties and operating conditions.…”

“…Transport of pure components and mixtures in zeolites has been modeled by the generalized Maxwell-Stefan diffusion approach, with adsorption described by single-or multi-site Langmuir isotherms, with some success [4][5][6]. For diffusion of a single component through zeolites, the Maxwell-Stefan model takes into account the fact that the flux is driven by the chemical potential gradient rather than the partial pressure gradient across the membrane.…”

Transient permeation of butanes through ZSM‐5 and ZSM‐11 zeolite membranes

“…For MaxwellStefan surface diffusion, the F-factor (Gardner et al, 2003) depends on the feed-side fractional coverage 0…”

“…Support resistance at the permeate boundary causes the Ffactors to increase (Gardner et al, 2003). When the permeate coverage is not zero, the F-factors must be determined iteratively, as described in the section on numerical solution of the transient model.…”