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In this work it was studied the efficiency of a photocatalytic process for the removal of Patent blue V. This dye is very difficult to remove by conventional treatments such as adsorption or coagulation therefore the photocatalytic process is a very interesting alternative for the removal this dye mainly because it does not require expensive oxidants and it can be carried out at mild temperatures and pressures. In this work it was tested the efficiency of Au-TiO 2 and Pt-TiO 2 photocatalysts in the Patent blue V removal. The Au-TiO 2 catalysts were prepared by two different methods: chemical reduction and photochemical deposition; Pt-TiO 2 catalysts were obtained only by photochemical deposition. In the synthesis of the catalysts prepared by photochemical deposition, it was evaluated the influence of some parameters, such as deposition time and the intensity of the light source over the physicochemical properties and photocatalytic activity of the materials obtained. An analysis of the effect of the catalyst dosage and initial Patent blue V concentration over the dye degradation efficiency was also attempted. In general, it was observed that the presence of Au or Pt on TiO 2 enhances the Patent blue V photodegradation; it was found that noble metal particle size and distribution on TiO 2 surface are important factors influencing the dye removal. The highest dye degradation was obtained over the 2 Au-TiO 2 catalyst prepared by photochemical deposition, using high light intensity and 15 minutes of deposition time during the synthesis. A discoloration and a total organic carbon (TOC) removal of 93 and 67% respectively, were obtained over this material after 180 minutes of UV irradiation. These values are higher than that the obtained on S-TiO 2 (discoloration and TOC removal of about 25% and 3%, respectively).

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Recebido em 23/1/09; aceito em 4/12/09; publicado na web em 8/4/10 Titania-supported Ir catalysts were used in the hydrogenation of furfural. Reactions were carried out in a stirred batch type reactor at 0.62MPa and 363K using a 0.10M solution of furfural in a 1:1 mixture n-heptane -ethanol as solvent. Catalysts containing 2 wt% of Ir were reduced in H 2 flow at different temperatures in the range 473-773K. The catalysts were characterized by H 2 chemisorption, TEM, TPR, TPD of NH 3 and XPS. Conversion of furfural is higher at lower reduction temperatures, but leads to byproducts whereas reduction at higher temperatures shows selectivity to furfuryl alcohol close to 100%.

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