Synthesis and characterization of ordered mesoporous silica membrane: Role of porous support and gas permeation study

In this work, the supported silica membranes were synthesized on various self-made symmetrical alpha-alumina supports having different pore sizes by spin coating method. The final synthesized membranes were further characterized by XRD, FESEM and FTIR analysis. Gas separation properties of the resultant supported ordered mesoporous silica membranes were evaluated by single gas permeation experiments. The results showed that the lower pore sized alpha-alumina supports can effectively reduce the surface defects of the silica layer and enhance the gas permeation properties of the supported silica membranes. The orders of the silica structure were also improved by reducing the pore size of the alpha-alumina supports. Steady-state single gas permeation using CO2, Ar, He and N-2 gases showed Knudsen diffusion mechanism for the membrane synthesized on the alpha-alumina support having lowest pore size of similar to 0.09 mu m. The other membranes having higher pore sized supports obeyed both Knudsen as well as viscous diffusion mechanisms. In addition, mixed gas permeation (20% CO2 and 80% N-2) studies were carried out using amino functionalized mesoporous silica membrane. (C) 2015 Elsevier Inc. All rights reserved.