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

Abstract In this work the preparation of cobalt spinel CoAl 2 O 4 is described. The technique of colloidal solution destabilization was used as the sol-gel process. The powder obtained from the dried gel was characterized by thermal analysis (thermogravimetric and differential), X-ray diffraction, infrared spectroscopy, and specific surface area measurement. Crystallization of CoAl 2 O 4 spinels occurs at about 400°C. The study of surface properties (surface charge and electrophoretic mobility) of the spinel powder fired at 600°C, in suspension in different electrolyte solutions (10 −3 molar ionic 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 the slip-casting method.