Coating and characterization of titania membrane on porous ceramic supports

In this article, we reported experimental results on the development of microstructure of the membrane layer deposited on a porous support. The changes in porosity and mean pore diameter were followed as a function of layer thickness. It was found that in addition to particle packing and sintering within the membrane layer, the porous structure of support surface also exhibited certain effects on membrane microstructure until a critical thickness was reached. After that, the porous characteristics of a membrane would be totally determined by the packing and sintering characteristics of particles. It was also shown that the surface roughness could be reduced from about 1.5 mu m of the support, to 0.8 mu m after coating with 0.5 mu m titania particle and further reduced to about 0.55 mu m after another coating with 30 nm titania colloids. With proper dispersing and coating procedures, we could reduce the mean pore diameter from about 1.5 mu m of the support to 0.12 mu m, while the gas permeability was only changed from 500 x 10(-7) to 250 x 10(-7) mol/m(2) s Pa.