2019 Volume 127 Issue 4 Pages 267-271
Porous ceramic filters made of MgAl2O4 spinel are promising due to their excellent thermal and chemical stability. In this study, toward future cross-flow ultrafiltration applications, reactive synthesis of porous MgAl2O4 membranes on a macroporous Al2O3-based ceramic tube has been examined. Fine (0.2 µm) and coarse (0.7 µm) α-Al2O3 powders and two types of MgO sources, i.e., MgO (∼2.8 µm) and MgCO3 (basic) [hydromagnesite Mg5(CO3)4(OH)2·4H2O] (∼5.5 µm) powders were used as starting materials for the reactive synthesis of porous MgAl2O4 membranes. For the intermediate layer, MgCO3 (basic) powder was favorable as a MgO source because it can clog up the large (15 µm) pores in the Al2O3-based tube. Meanwhile, for the top layer, MgO powder with finer particle size was favored to obtain homogeneous layer for ultrafiltration.