Characterization and Comparative Analysis of Nanometric Powders Obtained by High Energy Milling With and Without Acid Leaching For Photocatalytic Application

Reference	Presenter	Authors (Institution)	Abstract
06-009	Lucca Monteiro Silva Semensato	Semensato, L.M.(Universidade Federal de Alfenas); Pallone, E.M.(Faculdade de Zootecnia e Engenharia de Alimentos - FZEA); Maestrelli, S.C.(Universidade Federal de Alfenas); Mancini, M.H.(Universidade Federal de Alfenas); Storion, A.G.(Universidade Federal de Alfenas); Giraldi, T.R.(Universidade Federal de Alfenas); Estorari, L.F.(Universidade Federal de Alfenas);	Dyes are substances widely used in several industrial processes and are classified as a class of wastes very harmful to the environment if improperly discarded, especially regarding water resources. Heterogeneous photocatalysis is an alternative technique for decontamination, mostly regarding the use of multicomponent oxide systems for this purpose. Zinc oxide and Titanium dioxide, or titania, have been broadly investigated due to their heterogeneous photocatalytic degradation capabilities. The present paper aimed to investigate the effect of acid leaching in the properties of nanometric powders obtained by high energy milling in a SPEX type vibrating mill. This mill consists in a flask and hardened steel balls, which causes the contamination of the oxides by Iron. Thus, the influence of the presence of Iron and its absence (with the use of acid leaching) in the properties of the powders of the system ZnO:TiO2 obtained after milling for 2 and 4 hours were investigated. The precursors powders’ physico-chemical characteristics were evaluated using Nitrogen Physisorption (B.E.T.), X-Ray Diffraction (XRD), Scanning Electron Microscopy by Field Emission (SEM - FE), Thermogravimetric Analysis (TA) and particle size distribution. After the milling in duplicate, for each composition of the ZnO:TiO2 system (0:100, 25:75, 50:50, 75;25 and 100:0), every powder, whether or not followed by acid leaching, was characterized by X-Ray diffraction, evaluating the size of the crystallites by the Rietveld method. The results indicated that the HEM was efficient in obtaining nanopowders; however, the leaching process in all systems studied was not enough to remove all the iron present; it was also verified that Iron entered the material’s crystalline structure, which compromise the photocatalytic properties of the system. The authors thank FAPEMIG and CAPES for the financial support to this research.
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