ABSTRACT
Zeolite membranes, for their high thermal and chemical stability (high resistance to chlorine, oxidants, and solvents), can be used when the polymeric membranes cannot operate. However, the industrial application of zeolite membranes is limited by the costs and low reproducibility during the synthesis process. To date, their use at the industrial level is only represented by LTA zeolite membranes for organic solvent dehydration. Different methods for their preparation were developed; but the most used is the secondary growth for its different advantages such as easier operation, higher controllability in crystal orientation, microstructure and film thickness, and better reproducibility with respect to the in situ method. However, further improvements based on the preparation of reproducible defectfree zeolite membranes with larger area and suitable configuration (capillary or multichannel supports) are necessary. Another
important aspect to consider is the reduction in their manufacturing cost to facilitate their introduction in the industry. This chapter gives an overview of the methods for synthesizing nanostructured zeolite membranes. Besides, the chapter also illustrates the application of membranes in water desalination and membrane reactors. 5.1 IntroductionZeolites are hydrated crystalline aluminosilicate, having SiO44−and AlO45−tetrahedral groups as structural unit (Fig. 5.1). These units are connected to each other through shared oxygen atoms, giving a wide range of structures.
