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Effects of thermal crosslinking treatment on gas separation performance and stability of polymeric membranes
Martin-Gil, V. ; Hrabánek, Pavel ; Sysel, P. ; Fíla, V.
In this work, (4,4’-Hexafluoroisopropylidene) diphthalic anhydride (6FDA), 2,4,6- trimethyl-1,3-diaminobenzene (DAM) and 3,5-diaminobenzoic acid (DABA) were used to synthesize copolyimides with different ratios of DAM:DABA (2:1 and 9:1) as well as polyimide 6FDA-DAM in order to check the influence of acidic group from DABA in the membrane formation process as well as in the crosslinking treatment. The main aim of crosslinking treatment is to improve the CO 2 induced plasticization resistance of the membrane. Copolyimides were synthesized using two steps reaction: (i) synthesis of polyamic acid (PAA) and (ii) thermal imidization in solution. The obtained crosslinked membranes presented solvent resistance due to the transesterification of the polymer. Furthermore, it could be observed that the crosslinked membranes showed higher permeabilities for small gases (He and H 2 ) and for bigger gases (CO 2 and CH 4 ) permeabilities decreased slightly. It can be due to the densification of the membrane during the thermal treatment. However, this treatment presents highly promising results for H 2 recovery in syngas production or extraction of hydrogen from petroleum naphtha cracking streams
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Development of silane modified TS-1 nanoparticles as fillers for Mixed Matrix Membranes (MMM’s)
Martin-Gil, V. ; Lhotka, M. ; Hrabánek, Pavel ; Fíla, V.
In this work, Titanium Silicalite 1 (TS-1) was synthesized using different crystallization temperature (Tc = 180 °C, 160°C, 140°C), aging time (t aging = 1, 2, 3 and 7 days) and aging temperature (T aging = T room , 40 °C, 80°C) in order to get suitable nanoparticle size and good distribution of particle size for using them as a filler in MMMs. The TS-1 particles with different Si/Ti ratios (Si/Ti = 25 and 100) were functionalized using different amino silane coupling agents: 3-aminopropyltriethoxysilane (APTES), 3- aminopropyltrimethoxysilane (APTMS) and 3-aminopropylmethyldiethoxysilane (APMDES). Moreover, a new kind of silane coupling agents: 3- glycidoxypropyltriethoxysilane (GPTES), 3-glycidoxypropyltrimethoxysilane (GPTMS) and 3-glycidoxymethyldiethoxysilane (GPMDES) were also used. Tetrahydrofuran (THF), with a high dielectric constant (7.6), was used as solvent in order to control the surface modification and avoid pore blockage. The samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), as well as carbon dioxide methane and nitrogen adsorption measurements. The obtained results showed that aging temperature at long aging times have the main effect on the morphology of the particles meanwhile crystallization temperature influences gas adsorption properties. T aging higher than T room showed a great influence on the particle size at t aging = 7 days; shorter t aging did not show an observable influence on the particle size. Crystallization temperature influences the adsorption properties; at lower crystallization temperature, higher quantity of CO 2 adsorbed and lower quantity of CH 4 adsorbed. At last, suitable TS-1 filler with good size distribution and particle size about 200nm was obtained using Si/Ti = 100 and Si/Ti = 25, T c = 140 °C, T aging = 40 °C and t aging = 7 days.
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Polyimide based membranes for gas separation
Martin-Gil, V. ; Sysel, P. ; Hrabánek, Pavel ; Fíla, V.
The 6FDA-DAM:DABA membranes with different ratio DAM:DABA have been successfully prepared and tested in single gas permeation. The crosslinked membrane prepared by thermal treatment present highly promissing results for H2 recovery in syngas production, extraction of hydrogen from petroleum naphtha cracking streams or other chemical processes where the hydrogen as by product is generated.
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Separace uhlovodíků a CO2 na zeolitických MFI membránách
Dung Cong, T. ; Fíla, V. ; Hrabánek, Pavel ; Cílová, Z. ; Zikánová, Arlette
MFI zeolite membranes were prepared on stainless steel and ceramic supports by using hydrothermal synthesis method. The synthesized zeolite layers were compact and composed of randomly oriented crystals. Single component gases such as He, N2, CO2, SF6, CH4, i-C4H10, n-C4H10 and SF6 were used to test membrane permeation and separation characteristics. The effects of temperature and pressure drop on the separation properties of the membranes were also investigated using Wicke-Kallenbach method. Separation factors measured for CO2/CH4 and butane isomer mixtures were in the range of 1.2 – 4.1 and 5 – 20, respectively, depending on the operating conditions of the experiments and particular membranes.
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Preparation of silicalite-1 composite membranes
Hrabánek, Pavel ; Bernauer, B. ; Zikánová, Arlette ; Krystl, V. ; Kočiřík, Milan
Silicalite-1 crystal layers were synthesised on stainless steel and ceramic supports. The stainless steel supports manufactured by Trumem Int. (USA) and ceramic supports manufactured by Carborundum Electrite (Czech Republic) were chosen to prepare silicalite-1 composite membranes. In the case of stainless steel silicalite-1 composite membrane, the applied synthesis process has been recently developed by Gora et.al [1]. It was observed that the presence of silicalite-1 seeds influenced the membrane quality. A number of crystallization steps also played an important role. Ceramic silicalite-1 composite membranes were prepared on ceramic supports with the layers of randomly oriented silicalite-1 crystals. The disadvantage of the ceramic supports was their large pore size distribution and roughness of the surface. For this reason, several coating steps using ceramic glaze had to be used to reduce the pore size distribution and non-uniformity of the surface.
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Preparation and Characteristics of Porous Supports for Microporous Membranes Based on Al2O3 and SiO2
Fíla, V. ; Hrabánek, Pavel ; Juristová, K. ; Zikánová, Arlette ; Andertová, J. ; Bernauer, B.
Inorganic membranes have been used for separation of various liquid and gas mixtures due to their high mechanical and chemical resistance at elevated temperatures and pressures. The materials such as stainless steel, ceramics, polymers are available for preparation of the inorganic membranes. This paper is focused on the preparation and characterization of the composite membranes consisting of a ceramic support and layer of zeolite. The first part of the paper deals with the preparation of the porous ceramic supports, which are made using dry molding of a ceramic suspension mixed with the organic dispersant. The supports were characterized by permeation of N2, mercury porosimetry and SEM. The second part of the paper is focused on the preparation of microporous zeolite (MFI) layers on the supports. These microporous membranes were characterized by permeation and separation of H2 and iso-butane.
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