Title: Highly hydrogen-permselective zeolitic imidazolate framework ZIF-8 membranes prepared on coarse and macroporous tubes through repeated synthesis
Abstract: Highly hydrogen-permselective zeolitic imidazolate framework ZIF-8 membranes are prepared on coarse and macroporous Al2O3 tubes through a repeated synthesis strategy for the separation of H2/CO2, H2/CH4, and H2/C3H8 mixtures. Since the amino-groups of 3-aminopropyltriethoxysilane (APTES) can coordinate to the free Zn2+ centers and thus bind the growing nano-crystals directly, the nucleation and growth of well intergrown ZIF-8 membranes could be promoted through a repeated synthesis of the ZIF-8 layer on APTES-modified macroporous Al2O3 tubes. The SEM and XRD characterizations indicate that a dense and phase-pure ZIF-8 membrane with a thickness of about 25.0 μm can be formed on the alumina tubes by microwave synthesis at 105 °C for 3 h, and no cracks, pinholes or other defects were observed in the membrane layer. The ZIF-8 membranes were evaluated in single gas permeation and mixed gas separation. Attributed to the preferential adsorption affinity and capacity as well as a highly porous structure with nano-sized channels, the ZIF-8 membrane displays a high hydrogen permselectivity. For the separation of equimolar H2/CO2, H2/CH4, H2/C3H8 mixtures at 100 °C and 2 bar, the mixture separation factors of H2/CO2, H2/CH4, and H2/C3H8 are 5.6, 44.0, 328.6, with a H2 permeance of about 1.1 × 10−7 mol m−2 s−1 Pa−1, which is promising for potential applications in hydrogen purification and separation.
Publication Year: 2015
Publication Date: 2015-04-02
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 36
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