A composite TiO2 membrane supported by a planar or tubular porous metallic substrate has been developed using the wet powder spraying (WPS) method. Intermediate layers made of the same material as that of the support were found to be necessary to prevent the penetration of the powder suspension into the pores of the support during the spraying process. The morphology of the membrane was examined by LM, SEM and XRD analysis, and the characterization was performed by bubble-point, flow rate and stability tests. By using the ultrasonic wave and grinding methods it was possible to distinctly decrease the imperfections in the membranes. The TiO2 membrane itself has an average pore size of 0.11-0.12 mum, a thickness of 20-30 mum and an air flux up to 1.9 x 10(5) L/h m(2) bar. (C) 2004 Elsevier B.V. All rights reserved.