Helium permeation through mixed matrix membranes based on polyimides and silicalite-1

Mixed matrix membranes based on modified polyimides and silicalite-1 were prepared and studied. The novel preparation approach consists in improvement of the interfacial adhesion by employment of the coupling agent 3-aminopropyltriethoxysilane in such a way which leads to forming of chemical bonds between polyimide and silicalite-1. Firstly polyimide chains were endcapped by this agent which subsequently enabled their reaction with groups naturally present on silicalite-1 surface. Membranes with silicalite-1 content up to 60 wt. % were prepared and characterized by SEM, light microscopy and permeation of gases, prevailingly of He. The accessibility of sililicalite-1 pores prior to embedding and after embedding into polymeric matrices was studied by an iodine indicator technique. The permeability of membranes for gases was measured using a semi-open permeation apparatus with a small volume. Helium permeability depended on filler content and increased monotonously with the increasing content of filler. There were, however, significant deviations of the permeability dependences on filler content from shapes predicted by Bruggeman’s model. The qualitative explanation of the data disagreement with the model was proposed based on a stratification of mixed matrix membranes found by SEM

Dlouhodobá stabilita zeolitických MFI membrán

The aim of the study is to monitor zeolite membrane flux and separation factor as a function of total molar amount fed to the zeolite membrane surface area. The flux of permeating components (n-butane, isobutane) was reduced by factor of 1.6 for n-butane and 2.3 for isobutane. Ideal separation factor increased from 16 to 26 with increasing total molar amount of butane isomers fed to the membrane

Separace izomerů butanu použitím silikalitové kompositní membrány

Separation efficiency of the ceramic silicalite-1 composite membranes was studied with single component and equimolar mixture of butane isomers as a function of operating conditions (feed pressure, permeation temperature) using permeation apparatus MEMFIS. The separation factor for butane in the mixture with isobutane ranged between 10 and 20, which is an indication of high membrane quality. The flux of n-butane flux as a function of permeation temperature showed a maximum at 423 K

Preparation of silicalite-1 composite membranes

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

Vliv zrání a doby krystalizace na morfologii silikalitových krystalických vrstev

Influence of ageing and duration of crystallization on morphology of silicalite-1 crystal layers

Legislative Documents

Also, variously referred to as: House bills; House documents; House legislative documents; legislative documents; General Court documents

Helium permeation through mixed matrix membranes based on polyimides and silicalite-1

Mixed matrix membranes based on modified polyimides and silicalite-1 were prepared and studied. The novel preparation approach consists in improvement of the interfacial adhesion by employment of the coupling agent 3-aminopropyltriethoxysilane in such a way which leads to forming of chemical bonds between polyimide and silicalite-1. Firstly polyimide chains were endcapped by this agent which subsequently enabled their reaction with groups naturally present on silicalite-1 surface. Membranes with silicalite-1 content up to 60 wt. % were prepared and characterized by SEM, light microscopy and permeation of gases, prevailingly of He. The accessibility of sililicalite-1 pores prior to embedding and after embedding into polymeric matrices was studied by an iodine indicator technique. The permeability of membranes for gases was measured using a semi-open permeation apparatus with a small volume. Helium permeability depended on filler content and increased monotonously with the increasing content of filler. There were, however, significant deviations of the permeability dependences on filler content from shapes predicted by Bruggeman’s model. The qualitative explanation of the data disagreement with the model was proposed based on a stratification of mixed matrix membranes found by SEM

Legislative Documents

Also, variously referred to as: House bills; House documents; House legislative documents; legislative documents; General Court documents