UTN- FRC -Producción Académica de Investigación y Desarrollo - Artículos
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Item Novel and simple one-pot method for the synthesis of TiO2 modified-CMK-3 applied in oxidative desulfurization of refractory organosulfur compounds(Elsevier, 2018) Rivoira, Lorena Paola; Ledesma, Brenda Cecilia; Juárez, Juliana María; Beltramone, Andrea RaquelTi-CMK-3 carbon mesoporous was prepared using a novel synthesis method. This new method avoids the hard template synthesis used commonly. The precursors of silicon, carbon and titanium are incorporated together with the other components during the only step of the synthesis. The method developed here, allows reducing time and energy consumption by 60% and thus, the cost of the overall process of synthesis. Structural and textural characterization of the titanium modified-mesoporous carbon was performed by N2 adsorption, XRD, UV–Vis-DRS, XPS, Raman spectroscopy and TEM. The characterization results indicated that the textural and structural properties of the material synthesized by the short time method are comparable with the properties of the material prepared by the hard template method. Ti modified-mesoporous carbon was synthesized by dif- ferent methods in order to prepare catalysts to be tested in the oxidative desulfurization (ODS) of sulfur com- pounds. The catalyst prepared by the one-pot method is capable to oxidize high amount of sulfur (2000 ppm) in only 30 min of reaction time at 60–80 °C. The good performance and stability of the catalyst prepared using a novel synthesis method was attributed to well dispersed anatase nanospecies over the high area mesoporous carbon. Main advantage of the present study is the reduction of time and cost in the synthesis of the new material and the applicability for ODS reactions.Item Tetralin hydrogenation and ring opening of decalin over Ir-Pt-SBA-15(CICat, 2014) Vallés, Verónica Alejandra; Rivoira, Lorena Paola; Ledesma, Brenda Cecilia; Cussa, Jorgelina; Anunziata, Oscar Alfredo; Beltramone, Andrea RaquelA series of Ir and Pt modified SBA-15 were prepared by the consecutive wet impregnation method, with different content of each metal. The final catalysts were characterized by XRD, TEM and H2 chemisorption to study the effect of content of metal on the dispersion of iridium/platinum. The catalysts synthesized with similar percentage of both metals showed the best activity measured in tetralin hydrogenation and ring opening of decalin at mild conditions.Item Novel hybrid Ga-SBA-3 nanostructured material: Synthesis, Characterization and Applications(., 2018) Martínez, María Laura; Gómez Costa , Marcos Bruno; Beltramone, Andrea Raquel; Anunziata, Oscar AlfredoIn this work we study the incorporation of gallium in the structure of the SBA-3 mesoporous material, with the purpose of modifying the intrinsic acidity of the material using pyridine in order to determine the acidic sites that this material possesses. In addition, studies of adsorption / desorption of aniline and its subsequent polymerization on the mesoporous Ga-SBA-3, that gives the unique hybrids compound, with conductive characteristics similar to those of an inorganic semiconductor. Si-SBA-3 was prepared using CTABr and TEOS, as surfactant and Si source respectively. To obtain Ga-SBA-3 post-synthesis incorporation was employed. Ga-SBA-3 were dehydrated at 400 ° C under vacuum and then were exposed to vapors of pyridine / liquid aniline depending on the studies to be performed (pyridine to determine the acid sites of the material and aniline for subsequent polymerization) at vacumm. The in-situ polymerization of aniline was carried out to produce PANI/Ga-SBA-3. The final PANI/Ga-SBA-3 material was characterized by XRD, ICP, SEM-EDX, FTIR, BET. Direct current electrical conductivity measurements were performed using pellets and a four-probe technique, improving the contacts with a gold layer. Higher amount of polyaniline in conductive emeraldine salt form was found in PANI/Ga-SBA-3 composite, with respect to other composites reported in the literature. At room temperature (273 K), the electrical conductivity of PANI/Ga-SBA-3 was 2.5x10-3 S/cm, higher than its of Al-SBA-3 and Al-MCM- 41 homologs. To explain the conductivity of the composite (nanowire of PANI within Ga-SBA-3), we must consider the configuration of the nanostructured material and the type of PANI anchoring.Item Nanotubos de carbono de pared múltiple obtenidos con materila mesoporoso decorado con cerio-circonio(Universidad Tecnológica Nacional. Facultad Regional Córdoba, 2019) Rodríguez, Miguel Ángel; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Martínez, María LauraEn este trabajo, se ha empleado Ce-Zr-SBA-15 directamente como catalizador para la síntesis de nanotubos de carbono (CNT) a través de deposición química de vapor (CVD). Además del óxido de cerio, contiene nanocristalitos de óxido de circonio, que actúan como catalizadores para nanoestructuras de carbono. El rendimiento catalítico de este material se evaluó para la descomposición de etanol a 900 ° C, con flujo N2. La caracterización estructural del catalizador resultante se realizó por medio de microscopía electrónica de barrido (SEM). El carbono descompuesto de etanol absoluto se difunde a través de la superficie del material nanoestructurado y precipita en estructuras de carbono denominados Nanotubos de pared múltiple, los mismos pudieron visualizarse mediante microscopia electrónica de Transmisión (TEM), mostrando diámetros de los nanotubos de carbono que van desde 15 a 25 nm.Item Novel and simple one-pot method for the synthesis of titanium modified-CMK-3 applied in oxidative desulfutization of refractor y organosulfur compounds(Sociedad Mexicana de Materiales / Materials Research Society, 2018) Rivoira, Lorena Paola; Ledesma, Brenda Cecilia; Beltramone, Andrea RaquelTi-CMK-3 carbon mesoporous was prepared using a novel synthesis method. This new method avoids the hard template synthesis used commonly. The method developed here, allows reducing time, energy consumption and cost. Our primary aim in this work is to evaluate the ODS activity of the Ti-modified mesoporous carbon CMK-3, synthesized by the short time method, in order to achieve total removal of sulfur compounds from diesel fuel. The catalytic oxidation of the sulfur compound with hydrogen peroxide was carried out in a glass batch reactor, equipped with a magnetic stirrer, a thermometer and a condenser. In a typical run, the solid catalyst (60 mg) was suspended under stirring (750 rpm) in 20 mL of a solution of 500 ppm of S as DBT (or other) in acetonitrile. Then, appropriate amount of 30% aqueous H2O2 was added at constant temperature. The experiments were performed in a three-phase liquid-liquid-solid (L (oil) –L (solvent) –S (catalyst)) system, acetonitrile was used as solvent and dodecane as oil phase. Solution samples were recovered at various times. The products were analyzed by GC HP 5890 Series II with a HP-5 column and connected to FID and PFPD detectors, after filtration and eventually decantation step. The products were confirmed using a Shimadzu GCMS. Structural and textural characterization of the titanium modified-mesoporous carbon was performed by N2 adsorption, XRD, UV-Vis-DRS, XPS, Raman spectroscopy and TEM. The characterization results indicated that the textural and structural properties of the material synthesized by the short time method are comparable with the properties of the material prepared by the hard template method. Ti modified-mesoporous carbon was synthesized by different methods in order to prepare catalysts to be tested in the oxidative desulfurization (ODS) of sulfur compounds. The good performance and stability of the catalyst prepared using a novel synthesis method was attributed to well dispersed anatase nanospecies over the high area mesoporous carbon. Main advantage of the present study is the reduction of time and cost in the synthesis of the new material and the applicability for ODS reactions.Item Vanadium oxide supported on mesoporous SBA-15 modified with AI and Ga as a highly active catalyst in the ODS of DBT.(Universidad Tecnológica Nacional., 2017) Rivoira , Lorena Paola; Martínez , María Laura; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Martínez , María LauraVanadium oxides supported on mesoporous SBA-15 catalysts with different vanadium loadings were studied in the oxidative desulfurization (ODS) of dibenzothiophene as a model sulfur compound. The catalytic activity was improved when SBA-15 framework was modified by adding Al and Ga. Structural and textural characterization of the catalysts were performed by means of XRD, N2 adsorption, UVeVis eDRS, XPS, NMR, TEM, Raman, TPR and Py-FTIR. UVeViseDRS and Raman demonstrated that highly dispersed vanadium VO—3 species are responsible for the high activity in the sulfur removal. The Ga modified support with an intermediate V/Si ratio of 1/30 was the most active catalyst for ODS of DBT, using hydrogen peroxide as oxidant and acetonitrile as solvent. 100% of DBT elimination was attained at a short time in mild conditions. Gallium and aluminum incorporation into the support modified suc cessfully the nature of the SBA-15 surface by generating Bronsted and Lewis acidity. The interaction between the acid sites with the active vanadium sites improved the activity of the catalysts. The high dispersion depended on the vanadium loading and on the nature of the support. The more acidic support allowed better dispersion of the vanadium species due to stronger interaction metal-support. The reusability of the catalysts indicates that vanadium oxide supported on mesoporous SBA-15 modified with Ga and Al are potential catalysts for the ODS of dibenzothiophene.Item Hidrogenación e hidrodesulfurización de compuestos poliaromáticos utilizando Pt-Pd/AI203.(Universidad Tecnológica Nacional., 2016) Balangero , Gerardo Simón; Falcón , Horacio; Beltramone, Andrea Raquel; Beltramone, Andrea RaquelSe estudió la hidrogenación de compuestos poliaromáticos como tetralin y fenantreno en presencia de dibenzotiofeno y 4,6-dimetildibenzotiofeno utilizando un catalizador bimetálico Pt-Pd soportado sobre alúmina. El catalizador fue caracterizado por TEM, SEM y BET. Se obtuvo un catalizador con partículas metálicas bien dispersas y de muy pequeño tamaño. Los resultados fueron comparados con un catalizador comercial NiMo/Al2O3. Las reacciones se llevaron a cabo en un reactor de flujo continuo a 345°C y 500 psi (35 atm) variando los tiempos de contacto. Los resultados preliminares muestran que el catalizador desarrollado es más activo que el catalizador comercial. Se observó que los compuestos con mayor número de anillos aromáticos inhiben la velocidad de compuestos con menor número de anillos. Este efecto puede ser explicado en términos de una competitiva adsorción. Se realizó un test de desactivación y se observó que el catalizador no pierde su actividad luego de 20 horas de reacción.Item Vanadium oxide supported on mesoporous SBA-15 modified with AI and Ga as a highly active catalyst in the ODS of DBT.(Universidad Tecnológica Nacional., 2017) Rivoira , Lorena Paola; Martínez , María Laura; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Martínez , María LauraVanadium pentoxide supported on mesoporous SBA-15 catalysts with different vanadium loadings were studied in the oxidative desulfurization (ODS) of dibenzothiophene as a model sulfur compound. The catalytic activity was improved when SBA-15 framework was modified with Al and Ga as heteroatom substituting Si. Structural and textural characterization of the catalysts were performed by means of XRD, N2 adsorption, UV–Vis–DRS, XPS, NMR, TEM, Raman, TPR and Py-FTIR. UV–Vis– DRS and Raman demonstrated that highly dispersed vanadium pentoxide crystallites are responsible for the high activity in the sulfur removal. The high dispersion depends on the vanadium loading and on the nature of the support. The more acidic support allowed better dispersion of the vanadium species. The Ga modified support with an intermediate V/Si ratio of 1/30 was the most active catalyst for ODS of DBT, using hydrogen peroxide (H2O2) as oxidant and acetonitrile as solvent. 100% of DBT elimination was attained at a short time in mild conditions. Gallium and aluminum incorporation into the support modified successfully the nature of the SBA-15 surface by generating Bronsted and Lewis acidity. The interaction between the acid sites with the active vanadium sites improved the activity of the catalysts. The reusability of the catalysts indicates that vanadium oxide supported on mesoporous SBA-15 modified with Ga and Al are potential catalysts for the ODS of dibenzothiophene.Item Preparation of carbon nanotubes with hybrids nanostructure materials.(Universidad Tecnológica Nacional., 2017) Martínez , María Laura; Juárez , Juliana María; Gómez Costa, Marcos Bruno; Beltramone, Andrea Raquel; Juárez , Juliana MaríaCarbon nanotubes (CNT's) are allotropes carbon, like diamond, graphite and fullerenes. There are different types of CNT's, depending on the type of the graphite layers, it can be single wall carbon nanotubes (SWCNT's) and multi wall carbon nanotubes (MWCNT's). These nanomaterials show good physical properties such as their density, strength and thermal conductivity. The controllable synthesis of materials with the desired structure and dimensionality is of great significance in material science. In this work, the hierarchical carbon nanotubes (CNTs) were synthesized via a simple chemical conversion route by using Carbon Substrate/Fe3O4-SBA-15 hybrid (all in one). The synthesis of Carbon Substrate/Fe3O4-SBA-15 hybrid was carried out using Fe3O4- SBA-15 as a hard template and sucrose as carbon precursor. Sucrose was dissolved in a solution of H2SO4 in water and to this solution, Fe3O4-SBA-15 was added. The resulting mixture was dried at 373 K and then heated at 433 K for 6 h. A second impregnation was performed in order to ensure the filling of the template pores with the carbon precursor. To obtain the carbon nanotubes, the sample was placed in muffle at 1173 K under nitrogen flow (20mL/min) for 30 min. In order to remove the silica, the material was placed in an HF solution. The CNTs was filtered, washed and dried at 323 K. In the present work, we report the synthesis and characterization of CNTs materials of hybrid material. The material was characterized by X-ray diffraction (XRD) and the morphologies and structural features of the prepared materials were observed from the SEM and TEM images.Item Aniline adsorption and polymerization over gallium modified mesoporous material.(Universidad Tecnológica Nacional., 2018) Martínez , María Laura; Rivoira , Lorena Paola; Beltramone, Andrea Raquel; Anunziata, Oscar Alfredo; Anunziata, Oscar Alfredo; Rivoira , Lorena PaolaIn this work we study aniline polymerization over a mesoporous Ga-SBA-3 synthesized in our laboratory. In order to modify the intrinsic acidity of the mesoporous material gallium was incorporated into the structure by post synthesis wet impregnation method using gallium nitrate. Structural and textural characterization of the materials was performed by X-ray diffraction (XRD), ICP and EDX analysis, N2 adsorption-desorption and BET area analysis, FTIR and scanning electron microscopy (SEM). The catalytic material presented a ratio Si/Ga=32. Aniline is a weak organic base and an amphiprotic compound, so it can accept or donate protons. The polyaniline (PANI) exists in diverse ways presenting different chemical and physical properties. The protonated polyaniline feature the conductivity of a semiconductor material, over 100 S/cm. Toward achieve aniline adsorption, the solid gallium silicate was exposed to aniline vapours. The aniline adsorption was studied by infrared spectroscopy and the results obtained were evaluated so as to been able to polymerize it over the mesoporous material generating a unique polyaniline-host composite with new properties. Those polyaniline/hosts composites obtained by a polymerization in-situ technique were characterized by infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. Comparing to previous results FTIR analysis of the polyaniline/Ga SBA-3 composite (PANI/Ga-SBA-3) showed characteristics bands attributed to the quinoidal stretching (N=Q=N) and C-C stretching of the benzene ring. The low angle XRD analysis showed that the mesoporous structure was maintained in spite of the gallium incorporation. The absence of PANI peaks and G2O3 in the wide angle XRD pattern confirms that the polyaniline is adsorbed over the gallium silicate mesoporous surface and the gallium is well dispersed over the support.