Specific Aspects Attached to Ceramic Membranes

Major developments of membrane processes using ceramic membranes have been aimed at microfiltration or ultrafiltration applications. Up to now the most important applications for these membranes are found in aqueous media for the separation of particles, bacteria, colloids, macromolecules. Recently, ceramic nanofilters based on sol-gel derived microporous materials have been described [20]. They extend separation capability of ceramic membranes to ions and organics. 

12 — TRANSPORT AND FOULING PHENOMENA EM LIQUID PHASE SEPARATION 

Behind the general parameters (viscosity, transmembrane pressure, temperature, flow velocity) which can influence cross-flow filtration with ceramic membranes two aspects must be considered to be more specific of this sort of membrane. One is related to the geometry (tubular multichannel or honeycomb) found for the major part of commercially available membranes, the other is the amphoteric behaviour of metal oxides used in the preparation of these ceramic membranes. 

The tubular or monolith geometry of ceramic membranes proceeds from inherent constraints in ceramic material processing. Due to the mechanical properties of sintered ceramic materials which can be summed up in a high compressive resistance and a brittle character, cylindrical shapes offer the best compromise between pressure resistance and cross-flow filtration adaptability. Typical geometries for ceramic membranes are shown in Fig. 12.7. 

The problem encormtered with the first generation of tubular ceramic membranes was that they required a high pumping energy and a high volume/surface 

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