Synthesis of Fe2O3/Nb2O5 mixed oxides and its use as catalysts for methylene blue degradation

Reference	Presenter	Authors (Institution)	Abstract
06-118	Islanny Ouriques Brasileiro	Brasileiro, I.O.(Universidade Federal do Rio Grande do Norte);	Dyes are toxic and their uncontrolled release into rivers can endanger the health of the population and the environment. Advanced Oxidative Processes (AOPs) are a promising option for the treatment of textile effluents, since they are efficient technologies for the removal of recalcitrant organic compounds present in solution. Niobium pentoxide (Nb2O5) has been widely used in heterogeneous photocatalysis, however, its activity is limited under solar irradiation. Hematite (Fe2O3) represents a viable alternative due to its efficient absorption in the visible light range, although, its photocatalytic performance is harmed by the electron/vacancy recombination. Mixed oxides are materials composed of two or more semiconductors in order to achieve greater photocatalytic efficiency. Thus, the aim of this work was to synthesize and characterize mixed oxides of Fe2O3/Nb2O5 at different calcination temperatures and to evaluate the efficiency of these catalysts in the degradation of the methylene blue dye (MB) by two types of AOPs: heterogeneous solar photocatalysis and heterogeneous solar photo-Fenton. The semiconductors were produced from the modified Pechini method using the 60/40 and 80/20 mass ratios (%) of Fe2O3 and Nb2O5, respectively. The samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy coupled to a dispersive energy spectrophotometer (SEM/DES), infrared spectroscopy (IR) and specific surface area (BET) analysis. The obtained results showed that the union of the two oxides had a remarkable effect on the crystallinity and surface area, when compared with the pure Fe2O3 and Nb2O5. The catalytic activity of the mixed oxides synthesized under solar irradiation reached satisfactory performances in the oxidation of AM, suggesting that Fe2O3/Nb2O5 can be used as an efficient catalyst for the treatment of effluents containing dyes in the presence of H2O2 or not.
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