Characterization of membrane skin defects by gas permeation method

SEM analysis and gas permeability test to characterize polysulfone membrane prepared with polyethylene glycol as additive

“…The total gas permeation rate through an asymmetric membrane can be written in terms of Poiseuille flow and Knudsen flow in the porous medium, neglecting the contribution of the solution-diffusion flow through the nonporous medium. Then the following equation can be written for the total gas permeation rate Q g (m 3 /s) [22]:…”

“…Standard technique [21,22] was used to determine the mean pore radius (r m ) of the membrane with the assumption that the pores in the skin layer are cylindrical in nature. The total gas permeation rate through an asymmetric membrane can be written in terms of Poiseuille flow and Knudsen flow in the porous medium, neglecting the contribution of the solution-diffusion flow through the nonporous medium.…”

Gas and liquid permeation properties of modified interfacial composite reverse osmosis membranes

“…Gas permeation testing is a simple but useful separating layer characterization technique [7]. The ability of a membrane to separate a mixture of two gases depends on the chemical and morphological properties of the separating layer (Table 1), and is quantified by the membrane gas selectivity value:…”

Silica-Treated Ceramic Substrates for Formation of Polymer-Ceramic Composite Membranes

“…However, Knudsen flow in the modified substrates was verified by comparison of the selectivity of the silicatreated substrates for various gas pairs with the theoretical Knudsen selectivity. Also, for pure Knudsen flow a pressure normalized plot of flux vs mean pressure should give a straight line with a slope of zero for a low sorbing gas such as helium (Dullien, 1992;Uchytil et al, 1992).…”