Synthesis of Silicalite Membrane with an Aluminum-Containing Surface for Controlled Modification of Zeolitic Pore Entries for Enhanced Gas Separation
| Autor: | Zishu Cao, Antonios Arvanitis, Shaowei Yang, Xinhui Sun, Junhang Dong |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Bioengineering 02 engineering and technology 010402 general chemistry Fluid catalytic cracking lcsh:Chemical technology zeolite membrane pore modification gas separation 01 natural sciences Membrane technology lcsh:Chemistry Chemical Engineering (miscellaneous) Gaseous diffusion lcsh:TP1-1185 Gas separation Zeolite Process Chemistry and Technology Permeation 021001 nanoscience & nanotechnology 0104 chemical sciences Membrane Chemical engineering lcsh:QD1-999 0210 nano-technology Selectivity |
| Zdroj: | Processes, Vol 6, Iss 2, p 13 (2018) Processes; Volume 6; Issue 2; Pages: 13 |
| ISSN: | 2227-9717 |
| Popis: | The separation of small molecule gases by membrane technologies can help performance enhancement and process intensification for emerging advanced fossil energy systems with CO2 capture capacity. This paper reports the demonstration of controlled modification of zeolitic channel size for the MFI-type zeolite membranes to enhance the separation of small molecule gases such as O2 and N2. Pure-silica MFI-type zeolite membranes were synthesized on porous α-alumina disc substrates with and without an aluminum-containing thin skin on the outer surface of zeolite membrane. The membranes were subsequently modified by on-stream catalytic cracking deposition (CCD) of molecular silica to reduce the effective openings of the zeolitic channels. Such a pore modification caused the transition of gas permeation from the N2-selective gaseous diffusion mechanism in the pristine membrane to the O2-selective activated diffusion mechanism in the modified membrane. The experimental results indicated that the pore modification could be effectively limited within the aluminum-containing surface of the MFI zeolite membrane to minimize the mass transport resistance for O2 permeation while maintaining its selectivity. The implications of pore modification on the size-exclusion-enabled gas selectivity were discussed based on the kinetic molecular theory. In light of the theoretical analysis, experimental investigation was performed to further enhance the membrane separation selectivity by chemical liquid deposition of silica into the undesirable intercrystalline spaces. |
| Databáze: | OpenAIRE |
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