Nióbia como catalisador para a oxidação de contaminantes orgânicos:estudo do mecanismo de reação empregando ESI-MS

L. C. OLIVEIRA, T. RAMALHO, M. GONÇALVES, K. TATIANE, F.CEREDA1, M. NAZZARRO E K. SAPAG

Recife

Congreso; XV Congresso Brasileiro de Catalise; 2007

Sociedad Brasilera de Catalisis

In this work synthetic and natural niobia (Nb2O5) have been used to promote the hydrogen peroxide to O2 and the organic compounds (methylene blue dye as probe molecule) oxidation in aqueous medium. The niobias were characterized by N2 adsorption/desorption, XRD, TPR, XPS and FTIR measurements. The presence of reactive species on niobia surface strongly increased the rate of the oxidation of the methylene blue dye. The mechanism reaction was studied by ESI-MS analyses, kinetic data and XPS spectroscopy suggest that the organic oxidation is involving oxidizing species generated on the niobia surface. The results showed also that the Nb2O5 is a potential catalyst to active hydrogen peroxide to oxidize methylene blue dye for two competitive pathways: a heterolytic and homolytic mechanism via radical intermediates.