Synthesis and characterization of mixed matrix membranes for gas separation

Mixed-matrix membranes were prepared from Matrimid RTM and mesoporous ZSM-5 nanoparticles containing crystalline ZSM-5. The mesoporous ZSM-5 has both micropores (0.54 nm) and mesopores (2.7 nm), which were confirmed by XRD, nitrogen adsorption, and TEM. The Young's moduli and glass transition temperatures of mixed-matrix membranes are higher than those of pure MatrimidRTM membranes, suggesting that the polymer chains may penetrate into the mesopores. The ideal selectivity for H2/N2 separation increased from 79.6 for pure Matrimid RTM to 143 at 10% loading, while the selectivity of O2/N 2 increased from 6.6 for pure MatrimidRTM to 10.4 at 20% loading. The ideal H2/CH4 separation factor increased from 83.3 to 169 at 20% loading. The results suggest that the mesopores of the ZSM-5 material can provide good interfacial contact between the nanoparticles and the polymer, since the polymer chains can penetrate into the mesopores. The micropores of ZSM-5 crystals can provide size and shape selectivity.; A carbon aerogel was prepared by carbonizing a resorcinol-formaldehyde polymer gel at 800°C. Nitrogen adsorption shows the obtained carbon aerogel has both micropores (0.54 nm) and mesopores (2.14 nm). Zeolite A and zeolite Y nanocrystals were grown in the mesopores of the carbon aerogel, resulting in carbon aerogel-zeolite composites. TEM confirmed the existence of nanosize zeolite crystals in the carbon aerogel matrix. Higher selectivity for the CO2/CH4, O2/N2 and H2/N 2 separation were obtained for carbon aerogel-zeolite, carbon aerogel-zeolite-Matrimid RTM membranes. The small pore diameter of zeolite A and the affinity between the CO2 and zeolite crystals make it perfect for CO 2/CH4 separation.; Short single-walled carbon nanotubes (SWNT) functionalized with carboxylic acid groups were made and incorporated into MatrimidRTM to form mixed-matrix membranes. SEM images of mixed-matrix membranes cross-sections showed good dispersion and interfacial contact. Pure gas permeation showed 100% increase in permeability compared with pure MatrimidRTM, while the ideal selectivity of O2/N2, CO2/CH 4 and H2/N2 remained unchanged. The higher permeability can be attributed to the higher diffusivity in the SWNT.; A microporous metal organic framework Cu-4,4'-bipyridine-hexafluorosilicate (Cu-BPY-HFS), having a surface area of 2000 m2/g, was combined with MatrimidRTM polymer to form free standing films. The ideal selectivity of CH4/N2 increased from 0.95 to 1.21. This result suggests the Cu-BPY-HFS has a strong affinity towards CH 4 and favors the permeation of CH4. For CH4/N 2 gas mixtures, the selectivity increased from 0.95 to 1.7. The Cu-BPY-HFS's affinity towards CH4 and its large surface area increased the solubility of CH4 in the mixed-matrix membranes which led to higher selectivity towards CH4.; PMOs with different organic frameworks were prepared and incorporated into MatrimidRTM to form mixed-matrix membranes. Good interfacial contact was obtained because of the hydrophobic frameworks and mesopores. The permeabilities of all gases exhibit a substantial increase due to the fast diffusion in mesopores. The ideal selectivity for H2/N 2 and O2/N2 separation showed little change. There is no apparent difference when using PMOs with different organic frameworks. However, the CO2/CH4 ideal selectivity increased from 35 (pure MatrimidRTM) to 58 (10% MBS), then decreased to 40.; Matrimid membranes containing the Ag+-PMO (with ethenylene-bridged functional groups) complex were prepared. The Ag+ can bind pi-electrons from the C=C double bond of the ethenylene silica. The shift of C=C suggests interaction between the Ag+ and C=C pi-electrons, which helps to fix the Ag+ in the mesopores of the PMO. SEM images suggest good interfacial contact between the Ag+-PMO complex and the polymer. The propane/propylene mixture separation showed a 200% increase in selectivity, which is much lower than literature. The low selectivity can be attributed to the...