Cobalt spinel CoAl2O4 via sol-gel process: elaboration and surface properties

In this work the preparation of cobalt spinel CoAl2O4 is described. The tec hnique of colloidal solution destabilization was used as the sol-gel proces s. The powder obtained from the dried gel was characterized by thermal anal ysis (thermogravimetric and differential), X-ray diffraction, infrared spec troscopy, and specific surface area measurement. Crystallization of CoAl2O4 spinels occurs at about 400 degreesC. The study of surface properties (sur face charge and electrophoretic mobility) of the spinel powder fired at 600 degreesC, in suspension in different electrolyte solutions (10(-3) molar i onic strength), shows that the spinel material charge depends on the pH of the solution. The spinel sol was used for the preparation of membrane by th e slip-casting method. (C) 2001 Elsevier Science Ltd. All rights reserved.