Effect of pH on Characteristics of CoAl2O4 Nano Pigment Obtained by Combustion Synthesis

The aim of this research is to evaluate the efficiency of combustion synthesis method for production of nano CoAl2O4 and study the influence of pH (2.5, 7, and 10.5) on the characteristics of CoAl2O4 nano pigments. Gel formation, morphologies, specific surface area, and color of the powder were characterized using TG/DTA, XRD, SEM, TEM, BET, and UV-Vis techniques. The results indicate that spinel CoAl2O4 was formed independently of the different variables studied. According to the TEM figures, most particles calcined have average particle sizes less than 75 nm. Results show that pH has a strong effect on the procedure and characteristics of CoAl2O4. The best value of b* is seen at pH 2.5. In line with BET and Scherrer’s equation results, maximum specific surface area and minimum average particle size are at pH 7.