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

OLIVEIRA, L.C.A.; RAMALHO, T.C.; GONÇALVES, M.; CARVALHO, K.T.G.; CEREDA, F.; NAZZARRO, M.S; SAPAG, K.

Brasil

Congreso; 14º Congresso Brasileiro de Catálise; 2007

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