Development and characterization of tubular composite ceramic membranes using natural alumino-silicates for microfiltration applications

The preparation and characterization of porous tubular ceramic composite microfiltration membranes, using kaolins and calcium carbonates, were reported. The porous gehlenite (2CaO·Al2O3·SiO2) and anorthite (CaO·Al2O3·2SiO2) based ceramics were obtained by a solid state reaction. A ceramic support, sintered at 1250 °C, within an average pore size of about 8 ?m, 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 ?m and an APS value of about 0.2 ?m. This average pore size value was improved and considerably lower than those reported in the literature (0.5 ?m). 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.