Zeolite membranes are composites consisting of an active component – the zeolite – and a porous supporting material. Zeolites offer due to their tuneable pore size, their well-defined distribution of their pore size and their catalytical properties a wide spread research area. Supported on a porous material the enormous pressure drop, which occurs in zeolite beds is avoided and the resulted zeolite membranes can be used in different industrial processes e. g. gas separation processes. An additional advantage of zeolite membranes are their thermal and chemical stability compared to conventional polymeric membranes. Due to these properties, zeolite membranes are an excellent alternative for organic membranes in gas separation processes. As an active component, numerous types of zeolites like MFI, BEA, DDR or SAPO-34 can be supported on a porous material. Especially SAPO-34 is due to its small pore size and light acidity an excellent candidate for the preparation of zeolite membranes, which can be used not only in gas separation processes but also in catalytical processes. One of the reasons, why zeolite membranes are not used yet in large-scale industrial gas separation is the inevitable preparation of thin and defect-free zeolite layers on porous supports. Grain boundaries, generally formed throughout an imperfect intergrowth of zeolite crystals during the membrane synthesis lead to a reduction of selectivity in gas separation processes. Furthermore, inter-crystalline voids – defects – resulting due to the different expansion coefficient of the zeolite and the supporting material by a thermal treatment or a calcination step negatively effect the separation performance. Therefore, it is still a challenge to prepare perfectly intergrown zeolite layers or to close the generated defects post-synthetically. In this thesis, different possibilities are performed to close the defects directly in the preparation process or to minimize defects in the zeolite layer via a post-synthetic method. The healing of the defects during the preparation process is done via a multiple in-situ crystallization. For the post-synthetic defect closing, a simple method is proposed, wherein the intercrystalline defects are filled via a carbon based material resulting in a novel zeolite membrane type, the carbon integrated zeolite membrane.

Das generelle, wissenschaftliche Ziel dieser Dissertation ist Methoden für die Herstellung einer trägergestützten Zeolithmembranen mit möglichst dünnen und defektfreien Zeolithschichten zu entwickeln und zu testen. Dazu sollten zwei unterschiedliche Vorgehensweisen zum Defektschluss verfolgt werden. Zum einen die direkte Synthese einer dünnen, defektfreien Zeolithmembran mittels einer multiplen in-situ Kristallisation des Zeolithen, wobei die Bekeimung des jeweiligen porösen Trägermaterials reaktiv im ersten Kristallisationsschritt erfolgt. Zum anderen das postsynthetische Schließen von vorliegenden Defekten innerhalb der Zeolithschicht nach der Membransynthese durch Kohlenstoffintegration, wobei ein organisches Material infiltriert wird und nachfolgend eine Karbonisierung durchgeführt wird. Hierbei werden flexible Kohlenstoffnanostrukturen in die Defekte der Zeolithschicht eingebracht was zu einem neuartigen Membrantyp, den kohlenstoffintegrierte Zeolithmembran, kurz CiZM (Carbon integrated Zeolite Membrane) führt. Die Selektivität dieser kohlenstoffintegrierter Zeolithmembranen für die CO2/N2 Trennung liegt deutlich über der Selektivität von reinen Zeolithmembranen mit α-Al2O3 als Trägermaterial.