Micropores, alumina-based ceramics

They also formed the condensed polynuclear aromatic (COPNA) resin film on a porous a-alumina support tube. Next, a pinhole-free CMSM was produced by carbonization at 400-1,000°C [29], The mesopores of the COPNA-based caibon membranes did not penetrate through the total thickness of each membrane and served as channels which increased permeances by linking the micropores. CMSMs produced using COPNA and BPDA-pp ODA polyimdes showed similar permeation properties even though they had different pore stractures. This suggests that the micropores are responsible for the permselectivities of the carbonized membrane. Besides that, Fuertes [30] used phenohc resin in conjunction with the dip coating technique to prepare adsorption-selective carbon membrane supported on ceramic tubular membranes. 

An interesting extension of the range of vacuum filters is the capillary disc filter (Figure 4.26). This is a continuously operating, capillary action, ceramic dewatering filter, which eliminates the need for separate filter cloths. The filter medium is a disc, formed from two circles of sintered alumina, joined at their circumferences. The filter has several such discs mounted on a central horizontal shaft. The medium is practically inert in most solutions, and may be used in a broad range of water-based and solvent-based slurries. In operation, as the microporous ceramic discs rotate through... 

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