Porous ceramic supports for membranes prepared from kaolin and doloma mixtures

The present paper reports the in situ synthesis of porous ceramic supports from local kaolin and kaolin–doloma mixtures. These raw materials have been dictated by their natural abundance (low price) and their beneficial properties. In this work, four different processing routes have been presented. In addition, two support shapes are of particular interest: tubular and flat configurations, which are currently the most used supports in membrane research. Tubular configurations have been produced by extrusion method whereas flat configurations have been produced by both dry-pressing and roll pressing. The doloma addition to kaolin has a positive effect on the porosity ratio of supports compared to those prepared from kaolin alone. Moreover, the influence of the sintering temperature on the total porosity, average pore size, pore size distribution and strength of supports has been investigated. It has been found that higher sintering temperatures (1250 °C) were needed to obtain a uniform pore size distribution within total porosity ratios of 43 and, 51% when processes 3 and 2 were applied, respectively.