Use of silica sols in inorganic molecular sieving membranes
- Advanced Materials Lab., Albuquerque, NM (United States)
- Los Alamos National Lab., NM (United States)
Polymeric silica sols, were deposited on commercial {gamma}-alumina supports to prepare gas separation membranes. Optimization of the sol fractal dimension and radius of gyration and minimization of condensation rate led to formation of a discrete film with pores of molecular dimensions. Two coatings of this sol (A2{sup **}) led to a membrane with ideal separation factor of 7 for helium versus nitrogen after calcination to 400C (helium permeance 0.002 cm{sup 3}/cm{sup 2}-s-cm Hg). Partial sintering of these membranes resulted in a further reduction in pore size or narrowing of pore size distribution as evidenced by larger separation factors e.g. 9 for helium versus nitrogen (helium permeance 0.0028 cm{sup 3}/cm{sup 2}-s-cm Hg) with only one A2{sup **} coating. Single gas measurements also showed high ideal separation factors for helium versus methane, propylene, sulfur hexafluoride and carbon dioxide. The deposited A2{sup **} membrane was reacted with titanium isopropoxide (Ti(O i-Pr){sub 4}) to improve both its thermal and chemical stability and modify its pore size. This reaction led to an increase in the membrane selectivity to >300 for He versus N{sub 2} below to 120C, and CO{sub 2} versus CH{sub 4}, when measured below 200C. A2{sup **} was also used as a host matrix for preparing imogolite composite membranes that showed molecular sieving behavior.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Electric Power Research Inst., Palo Alto, CA (United States); National Science Foundation, Washington, DC (United States); Gas Research Inst., Chicago, IL (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 101225
- Report Number(s):
- SAND--95-1355C; CONF-940713--4; ON: DE95014885
- Country of Publication:
- United States
- Language:
- English
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