Synthesis and characterization of iron/niobium composites: catalyst for dye wastewater treatments

Abstract

A series of niobium/iron composites, Nb2O5/Fe(III) (%Fe(w/w) = 0.0, 2.0, 2.4 and 7.6), was prepared by conventional co-precipitation method. Powder XRD, 57Fe Mössbauer spectroscopy, temperature-programmed reduction and energy dispersive spectroscopy results suggested the formation of Fe-doped niobium oxide with deposition of hematite (α-Fe2O3) on the niobium oxide surface when iron percentage increases. The reactivity of the composites was investigated by the oxidation of the methylene blue dye as a model pollutant, in the presence of hydrogen peroxide (Fenton-like process) or ultraviolet light (photocatalytic process). The presence of iron oxide on the materials surface provided an increase in the catalytic activity of the composites when reactions were carried out in the presence of hydrogen peroxide (H2O2). The pure niobia was more effective for the reactions involving ultraviolet light.