Gas permeation through porous glass membranes: Part II: Transition regime between Knudsen and configurational diffusion

摘要: Abstract In Part I of this article an analysis four different mesoporous glass membranes with pores in a relative narrow size range between 2.3 and 4.2 nm was discussed focusing on the effects pore diameter surface properties membrane performances. It found that gas transport through these is primarily governed by Knudsen diffusion viscous flow if adsorption appears diffusion. Selectivities could be altered to some extent exploiting differences adsorbability gases but they were still rather limited. The strategy further reduce employed paper order improve separation. A flat based phase-separated alkali-borosilicate average 1.4 nm prepared study characteristics transition regime configurational mechanisms studied performing dynamic permeation measurements for several (He, Ar, N 2 , CO C 3 H 8 ) modified Wicke-Kallenbach cell temperature from 293 433 K using time lag method analysis. Additionally, equilibria measured standard volumetric technique at three temperatures (293, 323 353 K) pressures up 2.5 bar. permeability data observed experimentally are described theoretically. Ideal selectivity factors determined as ratios permeabilities pairs pure discussed.