A Highly Hydrogen Permeable Silica Membrane Supported on Porous Alumina

In previous chapters, the synthesis of a highly hydrogen selective membrane formed by the deposition of a silica layer on top of a Vycor glass substrate was discussed. In this chapter, the preparation of a composite membrane using a porous alumina support is described. This membrane showed a high hydrogen permeance of the order of 10 mol m s Pa at 873 K with selectivity of hydrogen over CH4, CO, and CO2 above 2000. The notable result is that the permeance of hydrogen is one order of magnitude higher than that of the silica membrane obtained on the porous Vycor support. The membranes were examined using Field Emission Scanning Electron Microscopy (FESEM) to give their cross-sectional morphology and Atomic Force Microscopy (AFM) to show their surface structure. The gas permeation properties of the membranes were discussed, and the transport of He and H2 gases through the silica membrane was analyzed using the statistical gas permeation mechanism described in Chapter 3.