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The preparation and characterization of porous tubular ceramic composite microfiltration membranes, using kaolins and calcium carbonates, were reported. The porous gehlenite (2CaO·Al 2 O 3 ·SiO 2 ) and anorthite (CaO·Al 2 O 3 ·2SiO 2 ) based ceramics were obtained by a solid state reaction. A ceramic support, sintered at 1250°C, within an average pore size of about 8 μm, a porosity of about 47% and a compression strength around 40 MPa, was prepared. The microfiltration active top layer was added on the support by a slip casting from clay powder suspensions. The novel microfiltration membrane layer has a thickness of 40 μm and an APS value of about 0.2 μm. This average pore size value was improved and considerably lower than those reported in the literature (0.5 μm). The performance of the novel microfiltration ceramic membrane was determined for evaluating both the water permeability and rejection. This proved the potentiality of the membrane produced in the microfiltration field. Moreover, the good adhesion, between the support and the active microfiltration layer membranes, was also proved. A correlation between microstructures of used powders and physicochemical properties was discussed. Finally, the origin of the unique two powder order membrane depositions was also proposed.

A B S T R A C TThe ceramic products are extremely interesting in the field of the membrane supports because of their mechanical resistance, chemical inertia, long working life, and thermal stability. This work is mainly focussed on ceramic supports rather than its deposited membranes because it constitutes about 99% of the filter mass. Therefore, replacing the more expensive starting materials (Al 2 O 3 ) by other low cost raw materials (kaolin and calcite) for supports fabrication is significantly important. Consequently, the supports for microfiltration (MF), ultrafiltration, and nanofiltration were prepared with local kaolin (DD2) and calcite mixtures. The choice of these raw materials is based on their natural abundance (low price). These supports were made by extrusion technique order to obtain tubular supports which were afterward sintered at 1,150˚C for 2 h. It has been found that supports had interesting characteristics; an average pore size of about 4 μm, a porosity ratio around 50.5%, and a three-point flexural strength ≈28 MPa. Moreover, the pore size distribution was almost mono-modal type. The surface and the cross-section morphologies observed through a scanning electron microscope were also homogeneous and do not present any possible macro defects (cracks, etc.) These supports were selected to be substrates for the membrane layers used in MF.

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