Reactive synthesis of porous MgAl2O4 membranes on a macroporous Al2O3 -based ceramic tube toward cross-flow ultrafiltration

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 mu m) and coarse (0.7 mu m) alpha-Al2O3 powders and two types of MgO sources, i.e., MgO (similar to 2.8 mu m) and MgCO3 (basic) [hydromagnesite Mg-5(CO3)(4)(OH)(2)center dot 4H(2)O] (similar to 5.5 mu m) 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 dog up the large (15 mu m) 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. (C) 2019 The Ceramic Society of Japan. All rights reserved.