Separation of gas mixtures using hollow fiber silica membranes
- Colorado School of Mines, Goldon, CO (United States); and others
The microstructure and surface chemistry of PPG microporous hollow fiber silica membranes was investigated by a variety of methods including FTIR spectroscopy, physical adsorption of Ar, and small angle X-ray scattering (SAXS). FTIR spectroscopy was utilized to monitor the amount of water in the silica membranes as a function of temperature and pressure. By annealing the membrane to 700 K, and then dosing with water vapor, the authors demonstrated that removal of physically adsorbed water is reversible. The pore size distribution of the silica fibers was determined by measuring the physical adsorption of Ar at 87 K. Since the Kelvin equation does not apply to pore sizes of molecular dimensions, the pore sizes were determined by using the Horvath-Kawazoe (H-K) potential function. The calculated average pore diameters were 5.5 {angstrom} for a 6 {angstrom} zeolite and 8.2 {angstrom} for the PPG fiber sample. By calculating the average pore diameter for the zeolite with a known structure, the authors were able to demonstrate that the H-K potential function predicts pore diameters within 10% of the actual pore diameter from the zeolite structure. In addition to the physical adsorption measurements, SAXS experiments were performed to acquire the pore size distribution of the fibers. By assuming the pores are spherical voids, an average pore size of approximately 13 {angstrom} was calculated. Changing the angle of incidence of the X-rays resulted in no detectable change in the intensity of the transmitted X-rays, indicating that the pores are oriented in a completely random configuration. High selectivities were obtained for O{sub 2}/N{sub 2} and CO{sub 2}/CH{sub 4} mixtures.
- OSTI ID:
- 213114
- Report Number(s):
- CONF-940713-; TRN: 96:001036-0032
- Resource Relation:
- Conference: 3. international conference on inorganic membranes, Worcester, MA (United States), 10-14 Jul 1994; Other Information: PBD: 1994; Related Information: Is Part Of ICIM{sub 3} 1994: Third international conference on inorganic membranes. Final program; PB: 148 p.
- Country of Publication:
- United States
- Language:
- English
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