TY - JOUR
T1 - Microporous SiO2/Vycor membranes for gas separation
AU - Levy, R. A.
AU - Ramos, E. S.
AU - Krasnoperov, L. N.
AU - Datta, A.
AU - Grow, J. M.
N1 - Funding Information:
The authors wish to thank K. K. Sirkar for stimulating our interest in this field, V. Sigal and J. Opyrchal for their technical assistance, as well as A. B. Shelekhin and Y. H. Ma of Worcester Polytechnic Institute for their valuable suggestions. Funding for this program was provided by a grant from the Hazardous Substance Management Research Center, a National Science Foundation Industry/University Cooperative Center and an Advanced Technology Center of the New Jersey Commission on Science and Technology.
PY - 1996/12
Y1 - 1996/12
N2 - In this study, porous Vycor tubes with 40 Å initial pore diameter were modified using low pressure chemical vapor deposition (LPCVD) of SiO2. Diethylsilane (DES) in conjunction with O2 or N2O were used as precursors to synthesize the SiO2 films. Both "single side" (reactants flowing on the same side of porous membrane) and "counterflow" (reactants flowing on both sides of porous membrane) reactant geometries have been investigated. The flow of H2, He, N2, Ar, and toluene (C7H8) was monitored in situ after each deposition period. Membranes modified by the "single side" reactants geometry exhibited good selectivities between small and large molecules. However, cracking in these membranes after prolonged deposition limited the maximum achievable selectivity values. Higher selectivities and better mechanical stability were achieved with membranes produced using the "counterflow" reactants geometry. Pore narrowing rate was observed to increase with oxidant flow (O2 or N2O). For membranes prepared using both oxidants, selectivities on the order of 1000:1 were readily attained for H2 and He over N2, Ar, and C7H8. As compared to O2, the use of N2O caused improvements in both the pore narrowing rate and N2:C7H8 selectivity. Membranes prepared using the "counterflow" geometry showed no signs of degradation or cracking after thermal cycling.
AB - In this study, porous Vycor tubes with 40 Å initial pore diameter were modified using low pressure chemical vapor deposition (LPCVD) of SiO2. Diethylsilane (DES) in conjunction with O2 or N2O were used as precursors to synthesize the SiO2 films. Both "single side" (reactants flowing on the same side of porous membrane) and "counterflow" (reactants flowing on both sides of porous membrane) reactant geometries have been investigated. The flow of H2, He, N2, Ar, and toluene (C7H8) was monitored in situ after each deposition period. Membranes modified by the "single side" reactants geometry exhibited good selectivities between small and large molecules. However, cracking in these membranes after prolonged deposition limited the maximum achievable selectivity values. Higher selectivities and better mechanical stability were achieved with membranes produced using the "counterflow" reactants geometry. Pore narrowing rate was observed to increase with oxidant flow (O2 or N2O). For membranes prepared using both oxidants, selectivities on the order of 1000:1 were readily attained for H2 and He over N2, Ar, and C7H8. As compared to O2, the use of N2O caused improvements in both the pore narrowing rate and N2:C7H8 selectivity. Membranes prepared using the "counterflow" geometry showed no signs of degradation or cracking after thermal cycling.
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U2 - 10.1557/JMR.1996.0402
DO - 10.1557/JMR.1996.0402
M3 - Article
AN - SCOPUS:0030380645
SN - 0884-2914
VL - 11
SP - 3164
EP - 3173
JO - Journal of Materials Research
JF - Journal of Materials Research
IS - 12
ER -