New Al2O3 Membranes and Catalyst Substrates: Nanoporous Alumina and Corundum for Ultra- and Microfiltration

Ceramic membranes and coatings on metal substrates are provided consting of pure corundum with pore sizes 10-300 nm. The pore size of alumina nanofiltration membranes is > 0.8 nm. Highly defect-free microstructures improve separation limits and the strength when sol/gel approaches are replaced by nanopowder processing. Associated with a new synthesis that avoids the intermediate formation of platelet-shaped boehmite, equiaxed constituent particles give rise to an improved permeability of the porous microstructures.