ABSTRACT
Attempts are being made to replace all thermally driven separation processes by membrane-based processes, as energy is becoming an important issue day by day. Main advantages of inorganic membranes are that they can be operated at elevated temperature (metal membrane can tolerate
4.1 Introduction ............................................................................................................................ 57 4.2 Preparation of Zeolite Membranes ......................................................................................... 58
4.2.1In Situ Crystallization ................................................................................................. 58 4.2.2Vapor Phase Transport ................................................................................................ 59 4.2.3Secondary Growth Synthesis ...................................................................................... 59 4.2.4 Intergrowth Supporting Substances ............................................................................ 59 4.2.5 Crystallization by Microwave Heating .......................................................................60 4.2.6Silica Nanoblock ......................................................................................................... 61 4.2.7Oriented Zeolite Membrane ....................................................................................... 62 4.2.8Bilayered Zeolite Membrane ...................................................................................... 63
4.3 Problems Associated with Crystal Structure .......................................................................... 63 4.3.1 Irregular Thermal Expansion ..................................................................................... 63 4.3.2Anisotropy of Mass Transport .................................................................................... 63 4.3.3Influence of Crystal Boundaries .................................................................................64
4.4Use of Zeolite Membranes ......................................................................................................64 4.4.1 Water Separation .........................................................................................................64 4.4.2 Gas Separation ............................................................................................................65
