Asymmetric capillary membrane of a carbon molecular sieve

Gas Permeation through Micropores of Carbon Molecular Sieve Membranes Derived from Kapton Polyimide

“…In some of the past studies 5,6,11 asymmetric membranes have been prepared, because the thinner skin layer formed on a porous support is desirable for practical use in providing higher fluxes. Our previous study, however, revealed that the microstructure and gas permeation properties of asymmetric CMS membranes prepared on the basis of the phase inversion technique were difficult to control and were sensitively influenced by preparation conditions particularly at the gelation step. The formation method 1,4,7 of repeating the coating−pyrolysis cycle for several times until no pinholes are depicted also needs time and special care.…”

“…One of the candidates is a carbon molecular sieve (CMS) membrane, which is obtained by pyrolysis of a polymeric precursor. The CMS membrane has extensively been studied and shown to exhibit excellent gas separation performance. − A distinctive feature is that the controlled pyrolysis of a precursor can yield a series of CMS membranes that possess micropores of desired dimension. Nevertheless, the factors determining the microstructure and gas permeation properties of CMS membranes are not completely open to control, because these properties are significantly affected by several factors and vary from sample to sample.…”

A novel carbon/ZSM-5 nanocomposite membrane with high performance for oxygen/nitrogen separation

“…1 For carbon membranes, the structure characteristics and gas separation performance mainly depends on the organic precursor and heat treatment process adopted. To date, many types of polymers have been tested as the precursor of carbon membranes such as poly(furfuryl alcohol), [2][3][4] poly(vinylidene chloride), 5 phenolic resins, 6,7 polypyrrolone, 8 coal tar pitch, 9 polyimide (PI) [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] and polyimide containing siloxane. [29][30][31] Though great progress has been made in the field of carbon membranes, it is not uncommon that a strong trade-off relationship exists between the permeability and the selectivity, i.e.…”

Alkene/alkane permselectivities of a carbon molecular sieve membrane

“…a molecular sieving effect. [7][8][9][10][11] In our previous papers, 12,13 CMS membranes prepared by pyrolysis of both flat and capillary Kapton polyimides had been reported to exhibit the highest gas permselectivities for inorganic gas pairs. Here, we report the excellent propene/propane permselectivity of a CMS membrane whose pore dimension has been slightly expanded.…”