Synthesis, characterization and methylene blue degradation of cobalt ferrite/niobium oxide composite calcined at various temperatures

Reference	Presenter	Authors (Institution)	Abstract
08-044	Sunday Joseph Olusegun	Olusegun, S.J.(Universidade Federal de Minas Gerais); Lara, L.R.(Universidade Federal de Minas Gerais); Mohallem, N.D.(Universidade Federal de Minas Gerais);	The difficulty of separating adsorbents after adsorption process has necessitated a paradigm shift to magnetic adsorbents that could be easily separated by an external magnet. This article describes the synthesis, characterization, and application of cobalt ferrite/niobium oxide which was prepared by precipitating niobium oxide at pH 9 on cobalt ferrite in ratio 2.5:1. The magnetic composite formed was spray dried, calcined at 300, 500 and 700 oC, and used for the degradation of methylene blue (MB). The composite was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and N2 adsorption-desorption isotherms. Magnetic measurements were performed on a magnetometer and susceptometer equipped with SQUID sensor. The magnetic saturation (Ms) is directly proportional to calcination temperature while the magnetic composite calcined at 700 oC has the highest Ms of 25 emu/g. The ability of the cobalt ferrite/niobium oxide composite to degrade methylene blue was found to decrease with increase in calcination temperature. This implies that crystallite growth of the composites does not favor the degradation process. Furthermore, magnetic composite calcined at 300 oC has the highest BET specific surface area (66 m2/g) and removal of MB from the solution.
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