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We report on the successful preparation of Fe-N codoped Titania powders, using TiO 2 Degussa P25, salt of Fe (II), and Urea. Modified Titania-based materials were characterized by SEM, EDS, BET, Raman, XRD diffraction and diffuse reflectance UV–vis spectroscopy measurements. The doping of TiO 2 induced a shift in the absorption threshold toward the spectral range, obtaining catalysts with a greater photoactivity than the one of pure Degussa P25. The degradation of 200 mL of a solution with 50 mg L − 1 acid blue BR dye in sulfate medium at pH 3.0 has been comparatively studied by electrochemical oxidation using a boron doped diamond anode (EO-BDD), Photocatalysis TiO 2 -Fe-N, and coupled material of EO-BDD/Photocatalysis TiO 2 -Fe-N. The solution was slowly degraded by EO-BDD (25%) and single Photocatalysis TiO 2 -Fe-N because of the low rate of dye degradation and its colored by-products with hydroxyl radicals generated at the BDD anode and catalyst surface from water oxidation (29%), whereas the solution was more rapidly degraded using coupled material of EO-BDD/Photocatalysis TiO 2 -Fe-N (82%), owing to the additional generation of hydroxyl radicals from the photocatalysis of TiO 2 -Fe-N and BDD anode. [ABSTRACT FROM AUTHOR]

Pt nanoparticles were obtained via the thermal decomposition of (NH4)2[PtCl4] (diammonium tetrachloroplatinate) by heating from room temperature to 760 °C. The thermal decomposition process was analyzed using thermogravimetric analysis (TGA) and differential thermal analysis (DTA), X-ray thermodiffraction and infrared spectroscopy. The size and structure of the platinum particles were analyzed using transmission electron microscopy (TEM). The electrochemical activity of Pt particles was assessed by cyclic voltammetry in 0.5 M H2SO4. The TGA and DTA results suggested that the thermal decomposition of the precursor proceeded in two stages: loss of NH4Cl at ~300 °C, followed by loss of NH4Cl and Cl2 at ~372 °C. Metallic Pt particles were then produced at temperatures of 372 °C and above. At 760 °C, the mean ± SD size of the Pt particles was (4.1 ± 1.6) nm, as determined from TEM measurements. In cyclic voltammetry (CV) measurements, an electrode comprised of glassy carbon and Pt particles in 0.5 M H2SO4 exhibited behavior similar to that observed using a polycrystalline Pt electrode. [ABSTRACT FROM AUTHOR]

Abstract: Spherical submicrometer-sized silica particles were prepared by the Stöber process, from a reaction mixture containing tetraethoxysilane, ammonia and ethanol, and deposited onto silicon wafers. While the properties of these SiO2 particles depend on their size, size distribution and shape, monodisperse spherical particles were obtained with a narrow size distribution. The samples were then irradiated at room temperature with Si ions at two energies (4MeV and 6MeV) and fluences up to 5×1015 Si/cm2, at an angle of 45° with respect to the sample surface. The size, size distribution and shape of the silica particles were determined using scanning electron and atomic force microscopes. By means of the Si ion irradiation, the as-prepared spherical silica particles can be turned into ellipsoidal particles, as a result of an increase of the particle dimensions perpendicular to the ion beam and a decrease in the direction parallel to the ion beam. This effect increases with the ion energy and fluence, and depends on the electronic energy loss processes to which the impinging ions are subjected. Our results also suggest that the particle deformation is more important in the case of larger as-prepared silica colloids. [Copyright &y& Elsevier]

It shows a process for overlap signals separation by fitting to Gaussians, with aid of Excel program. This process was applied, to quantitative determination of the high current density electro plating Zn-Ni alloys, obtained by Differential Pulse Polarografia DPP. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the use of coagulation/flocculation (CF) and electrochemical oxidation (EO) processes to purify vinasse that had already been biologically treated (vinasse BT). The CF process was analyzed as a function of the concentration of the coagulant (FeCl3) and the pH of the vinasse BT. After the CF process, EO was performed by potentiostatic electrolysis with a Ti/RuPb(40%)O x anode and Ti/PtPd(10%)O x cathode. The EO process was analyzed as a function of pH of vinasse CF treated and electrolysis time. The efficiencies of the CF and OE treatments on the vinasse BT were quantified in terms of the removal of chemical oxygen demand (COD), color and turbidity. The experimental results showed that the CF process with a coagulant concentration of 20g/L and a pH of 8.4 removes a significant amount of COD (84%), color and turbidity (∼99%). The subsequent EO step satisfactorily complemented the purification of vinasse BT by CF, yielding removal efficiencies of more than 95% for COD and on the order of 100% for color and turbidity. We suggest that the mineralization via electrochemistry took place by indirect oxidation, mediated by active chlorine derived from FeCl3 added during the CF treatment step. [Copyright &y& Elsevier]