Transport of Gas Through CMSMs

Mass transfer of gas through a porous membrane can involve several processes depending on the pore stmcture and the solid [1]. There are four different mechanisms for the transport Poiseuille flow Knndsendiflusion partial condensation/capillaiy diffusion/selective adsorption and molecular sieving [2, 3]. The transport mechanism exhibited by most of carbon membranes is the molecular sieving mechanism as shown in Fig. 2.1. The carbon membranes contain constrictions in the carbon matrix, which approach the molecular dimensions of the absorbing species [4], 

Ismail et al., Carbon-based Membranes for Separation Processes, 

Carbon molecular sieve membranes suitable for gas separation have been prepared by pyrolyzing thermosetting polymers. CMSMs with pore diameter 3-5 A have ideal separation factors, ranging from 4 to more than 170 for various gas pairs [2]. The permeation characteristics of the molecular sieve carbon membrane can be varied by changing the high temperature treatment parameters [8]. 

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