Zeolite membranes are selective barriers, which can be supported or not, and prepared with well-defined aluminosilicate crystalline structures having a uniform and well-defined porous framework. Zeolites are attractive molecular sieve materials which have been used for a long time as adsorbents, catalysts, and softeners in detergents (ion-exchange properties). Since the early 1990s, zeolite membranes attracted considerable attention in many research and industrial groups, exploring their potential for the continuous separation of liquids, gas, and vapors, for chemical synthesis, pollution abatement, catalytic reactors, micro-reactors, sensors, electrodes, and optoelectronic devices (Caro and Noack 2008; Julbe 2007). Among the 229 currently known zeolitic framework type codes assigned to date by the International Zeolite Structure Commission (www.iza-online.org), less than 10 % have been prepared in a form of membrane. The most studied membrane...