Phase Development in Sol Derived Microporous Membranes for Gas Permselectivity

A sol-gel route has been used to produce a nanoporous membrane for the separation of greenhouse gases from power plants at elevated temperatures (700–900 K). The membrane has a controlled pore size distribution and is multiphasic, in order to prevent grain growth and pore coarsening. The alumina/titania diphasic ceramic was obtained from alkoxide precursors with additional magnesium or lanthanum doping to stabilize low temperature phases and to provide possible chemisorption of CO2. It was found that both Mg and La stabilized the -alumina phase to higher temperature by as much as 200 K, although Mg is less effective.