Sodalite membrane has been successfully fabricated on tubular porous alpha-Al2O3 supports by secondary growth method with vacuum seeding. In the seeding process, the colloidal seeding particles were agglutinated not only onto the surface of alumina support but also within the pores by vacuum sucking method. To obtain defect-free sodalite membrane, the sodalite crystals were grown directly on the alumina support in a mixture solution containing alumina and silica species under the hydrothermal reaction condition. The as-synthesized socialite membranes were characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The thickness and the quality of sodalite membrane could be controlled by the hydrothermal reaction time (12 similar to 24 h) and temperature (100 similar to 150 degrees C) under the mother solution of 5Na(2)O:2SiO(2):Al2O3:1000H(2)O. (c) 2005 Elsevier B.V. All rights reserved.