Gas permeation and separation by aqueous membranes immobilized across the whole thickness or in a thin section of hydrophobic microporous celgard films

An experimental study of the preparation and gas permeation characterization of aqueous membranes immobilized across the whole thickness or in a thin section of microporous hydrophobic Celgard 2400 and 2500 polypropylene films is described. Such films are identified as fully exchanged immobilized liquid membranes (ILMs) and ultrathin ILMs, respectively. Pure component permeation of N₂ and separation characteristics of CO₂N₂ mixtures through fully exchanged aqueous ILMs have been studied in the range of 127-1106 cmHg applied pressure difference. The values of the tortuosity factor for the Celgard 2400 and 2500 support films have been determined over a wide pressure range and compared with other independent estimates reported in the literature. Pure N₂ permeation and separation characteristics of CO₂N₂ mixtures through ultrathin ILMs prepared from 0.00254 cm thick ILMs of pure water by controlled evaporation of water in Celgard 2400 films have been described. The stability of fully exchanged and ultrathin ILMs of pure water in Celgard films for pure N₂ permeation and separation of CO₂N₂ mixtures upto pressures of about 1100 cmHg and over extended periods of operation has been studied.