Effect of drying process and calcination on the structural and magnetic properties of cobalt ferrite

Abstract Synthesis of CoFe 2 O 4 nanoparticles was carried out using a co-precipitation method. The resulting precipitate was dried by using conventional method (oven), and spray drying process. The products obtained from the two drying processes were calcined at 500 and 700 °C; and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) transmission electron microscopy (TEM), and N 2 gas adsorption technique. Magnetic measurements were performed on a SQUID magnetometer. The magnetic saturation value (76 emu g −1 ) of the spray dried cobalt ferrite calcined at 700 °C (SD-700) was higher than its corresponding oven-dried sample. The as-received spray dried CoFe 2 O 4 nanoplates (SD-100) has the highest BET specific surface area (138 m 2  g −1 ), while the oven-dried sample calcined at 700 °C (OD-700) has the lowest area (47 m 2  g −1 ). Cobalt ferrite samples obtained from the two drying processes were briefly applied to adsorb methylene blue solution as a cationic dye model to know the effect of drying process on the adsorption of dye. The studies showed that all the spray dried samples performed better in adsorbing methylene blue (MB) solution. Energy-filtered TEM (EFTEM) analysis that was carried out on SD-700 ascertained the adsorption of MB on its surface.