Inorganic membranes

Inorganic membranes consist of oxides, or metals, and can be present in multi-layer supporting structures, or as self-supporting structures. Dense membrane materials are ideally selective for O-2 or H-2 molecules. Micro-porous membranes (0.5-2 nm) can be highly selective for CO2, H2O and hydrocarbon. Meso-porous membranes (2-50 nm) are used as supporting structures, or in water purification. Macro-porous layers (>50 nm) are used as supporting structures and particulate filtration applications. Compared to polymeric membranes, inorganic membranes can be more selective and permeable, and can withstand more extreme conditions. To make them fully competitive their cost price must be reduced by improvements in processing, introduction of rapid fabrication methods, and possibly incorporation in hybrid, polymeric structures.