Facultad Regional Córdoba

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Author: search.filters.author.Ponte , María Virginia

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    Sulfur elimination by oxidative desulfurization with titanium-modified SBA-16.
    (Univesidsad Tecnológica Nacional., 2015) Rivoira , Lorena Paola; Vallés , Verónica Alejandra; Ledesma , Brenda Cecilia; Ponte , María Virginia; Martínez , María Laura; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Martínez , María Laura; Ponte , María Virginia; Ledesma , Brenda Cecilia; Vallés , Verónica Alejandra
    TiO2-modified mesoporous SBA-16 and titanium-substituted mesoporous SBA-16 were developed and tested in the oxidative desulfurization (ODS) of dibenzothiophene prevailing in liquid fuel. Pure TiO2 was used as reference. The titania-based catalysts were characterized by chemical analysis, XRD, EDX and TEM. The titanium state as tetrahedral (in Ti-SBA-16 sample) or octahedral (in TiO2/SBA-16 sample) coordination surrounding in the silicate matrix was determined by XPS, UV–vis DRS, FTIR, Raman and XANES. We assessed the impact exerted on performance of different reaction variables, including (nature and amount of the active catalytic species, phase system, molar ratio of oxidant H2O2 and DBT, reaction temperature, nature of the substrate and reuse of catalysts). In addition, we carried out a kinetic study and the activation energy was determined. We achieved 90% of S removal from a 0.2 wt.% dibenzothiophene solution at 60 ◦C in less than 1 h of reaction. The best catalytic results are obtained with high exposed surface of nanometric TiO2 species of TiO2/SBA-16 sample. The activated catalyst is very active in ODS reaction and can be reused four times with no loss in activity.
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    Optimization of the synthesis of SBA-3 mesoporous materials by experimental desing.
    (Univesidsad Tecnológica Nacional., 2015) Ponte , María Virginia; Rivoira , Lorena Paola; Cussa , jorgelina; Martínez , María Laura; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Anunziata; Cussa , jorgelina; Rivoira , Lorena Paola
    SBA-3 mesoporous materials are characterized by hexagonal regular arrangements of channels with diameters >2 nm, high specific surface areas and high specific pore volumes. In the work reported herein, experimental design-response surface methodology (RSM) is used to model and optimize the synthesis conditions for SBA-3 mesoporous materials. In this study, we evaluate the influences of surfactant/silica source molar ratios, aging times, temperature and pH on the synthesis of SBA-3 mesoporous materials by analyzing the XRD intensities pertaining to the [100] signal. Response surfaces were obtained using the BoxeBehnken design, and the combination of reaction parameters was optimized. By applying statistical methodology, higher levels of the objective function (XRD intensities pertaining to the [100] signal) were obtained using cetyltrimethylammonium bromide (CTAB)/tetraethyl orthosilicate (TEOS) molar ratios of 0.07 and 0.16, HCl/TEOS molar ratios of 8 and 11, reaction temperatures of 35 and 45 ◦C and aging times of 12e24 h. The mesoporous SBA-3 samples obtained were characterized using small-angle X-ray powder diffraction (XRD), BET, FTIR and 29Si NMR-MAS, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
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    Sílica Gel como fuente de silicio: Síntesis y caracterización de matrial mesoporoso.
    (Univesidsad Tecnológica Nacional., 2015) Ponte , María Virginia; Martínez , María Laura; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Martínez , María Laura
    El material mesoporoso SBA-3 fue sintetizado mediante el método sol-gel, utilizando silicato de sodio como fuente de silicio y bromuro de hexadeciltrimetilamonio (CTAB) como agente director de estructura en condiciones acidas. El silicato sódico se generó in-situ por disolución de silica gel en NaOH. Se estudió el efecto de la variación de temperatura, la concentración de NaOH, y el tiempo de reacción. El mejor material mesoporoso con estructura SBA-3 fue obtenido con las siguientes condiciones de síntesis: temperatura: 25ºC; tiempo de reacción: 45min; concentración de NaOH: 0.8M.
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    Eliminación de azufre mediante desulfuración oxidativa con Ti-SBA-16. Parte I. Síntesis y caracterización.
    (Univesidsad Tecnológica Nacional., 2015) Rivoira , Lorena Paola; Vallés , Verónica Alejandra; Ledesma , Brenda Cecilia; Ponte , María Virginia; Martínez , María Laura; Beltramone , Andrea Raquel; Martínez , María Laura; Ponte , María Virginia; Ledesma , Brenda Cecilia; Ledesma , Lorena Paola; Vallés , Verónica Alejandra
    Se desarrollaron catalizadores tipo SBA-16 modificados con Ti como TiO2 y como heteroatomo y se probaron en la desulfuración oxidativa (ODS) del dibenzotiofeno predominante en el combustible líquido. Se utilizó TiO2 puro como referencia para comparar la actividad catalitica. Los catalizadores fueron caracterizados mediante análisis químico, XRD, EDX y TEM. El estado de coordinación tetraédrico del titanio (en la muestra de Ti-SBA-16) u octaédrico (en la muestra de TiO2/SBA-16) en la matriz de sílice se determinó por XPS, UV-vis DRS, FTIR, Raman y XANES. La actividad catalítica se muestra en la Parte 2 de este trabajo.
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    Synthesis of SBA-1, SBA-3 and SBA-7 mesoporous materials. Study of the effect of time and temperature.
    (Univesidsad Tecnológica Nacional., 2018) Martínez , María Laura; Ponte , María Virginia; Falcón, Horacio; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Ponte , María Virginia
    In recent years, physicists, chemists and engineers have focused their research on the design of new functional materials. In the synthesis and control of materials in nanometer dimensions, the aim is currently directed towards the development of systems and devices that take advantage of chemical properties and physical principles, where their causes lie in the nanometer scale. Although there are numerous investigations about the synthesis of mesoporous materials from inorganic silicon salt, for example the synthesis of SBA-3. Ting et al [1] studied the synthesis of SBA-1; they obtained mesoporous SBA-1 with cubic structures, with a high porous system, by utilizing agents’ routers short chain structure such as the dodecyltrimethyl ammonium chloride. Recent research also showed that the formation of mesophases is affected by the presence of the counter ions and templates or surfactants can adopt a mesophase or other phases. So, Che et al. [2] found a phase shift 2D-hexagonal cubes from P6mm to Pm3n. We have published results for synthesis of SBA-3 with silica gel as silica source; we have found that the formation of mesophase is function of NaOH concentration in the dissolutions of silica gel. The influence of reaction temperature, time and NaOH concentration was investigated. During studies for the best synthesis conditions for synthesis of SBA-3, we also obtained SBA-1 and SBA-7 mesoporous materials.