UTN- FRC -Producción Académica de Investigación y Desarrollo
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Item Superacid Mesoporous Carbons Based on Sulfated Zr.(Univesidsad Tecnológica Nacional., 2020) Anunziata , Oscar Alfredo; Martínez , María Laura; Martínez , María LauraIn this brief communication we report the successful preparation of a promising material with acidic properties from starch-derived mesoporous carbon (SMC), functionalized with sulfated zirconia. The process of assembling P123, starch, zirconia and silicon produces ordered mesoporous carbon modified with Zr. Reaction time and temperature are essential to avoid the appearance of poorly assembled or unsightly structures, reducing the surface area and the size of the pores. Zr-SMC has a surface area of approximately 1300 m2 g -1 , and the total pore volume of 0.94 cm3 g -1 , composed mainly of mesopores with an average pore size of 3.5 nm. The composition of the surface and the chemical states of the elements did not reveal ZrO2 as isolated clusters. Through the thermodesorption of the pre adsorbed ammonia in the sulfated Zr-SMC, the total ammonia retained is 1.80 mmol / g at high temperature, exhibiting medium to strong acidity.Item Hap/LP-SBA15 Nanocomposite for efficient removal of fluoride from contaminated water.(Univesidsad Tecnológica Nacional., 2020) López, Claudia; Cussa, jorgelina; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Cussa, jorgelinaHydroxyapatite (HaP) composites and highly ordered large pore mesoporous silica, such as LP-SBA 15 (Large Pore-SBA-15), were developed, characterized by XRD, BET, FTIR, and HRTEM, applied to fluoride removal from contaminated water. The proposed procedure to prepare HaP/LP-SBA-15 was successful, which acts as supports to anchor the HaP crystals, in nanometer-scale (<12 nm), with higher fluoride retention from contaminated water. The free OH- groups of HaP nanocrystals, inside the host, permitted fluoride retention with high capacity. The fluoride holding activity was over 3 orders of magnitude higher than pure HaP.Item Hydrogenation of tetralin in presence of nitrogen using a noble-bimetallic couple over a Ti-modified SBA-15.(Univesidsad Tecnológica Nacional., 2016) Vallés , Verónica Alejandra; Ledesma , Brenda Cecilia; Pecchi, Gina; Anunziata , Oscar Alfredo; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Ledesma , Brenda CeciliaMonometallic Pt- and bimetallic Pt-Ir-modified Ti-SBA-15 were used in the hydrogenation of tetralin to decalin in the presence of 150 ppm of N as quinoline and indole at 250 ◦C and 15 atm of pressure of hydrogen, using a Parr reactor. The catalyst was synthesized using sol-gel method and Ti was added during the synthesis using Tetraethyl Orthotitanate. Pt/Ir was added by wetness impregnation. The catalysts prepared were extensively characterized by X-ray diffraction (XRD), N2 adsorption isotherms, UV–vis DRS, Raman spectroscopy, XPS, TEM-EDS and TPR. UV–vis-DRS and Raman spectroscopy confirmed that Ti was incorporated in tetrahedral coordination in the framework of the SBA-15. The analysis showed that the mesoporous structure was maintained after metal incorporation and Ti incorporation helps to reduce significantly the size of the metals clusters and improves its dispersion considerably. Pt-Ir/Ti-SBA 15 was the most active catalyst. The experimental data were quantitatively represented by a modified Langmuir-Hinshelwood type rate equation. The preliminary results show these materials as a promising catalyst for HDT reactions.Item Experimental desing optimization of the tetralin hydrogenation over Ir-Pt-SBA-15.(Univesidsad Tecnológica Nacional., 2015) Vallés , Verónica Alejandra; Ledesma , Brenda Cecilia; Rivoira , Lorena Paola; Cussa , jorgelina; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Cussa , jorgelina; Rivoira , Lorena Paola; Ledesma , Brenda CeciliaExperiment design-response surface methodology (RSM) is used in this work to model and optimize two responses in the hydrogenation of tetralin to decalin using bimetallic Ir–Pt-SBA-15 catalyst. In this study, we analyze the influence of the nature of the catalyst (metal molar fraction and metal loading), the catalyst/substrate ratio and the temperature of the reaction as factors for the design. The responses analyzed were conversion at 3 h and at 5 h of reaction time. The response surfaces were obtained with the Box– Behnken design, finding the best combination between the reaction parameters that allowed optimizing the process. By applying the statistic methodology, the higher levels of the two objective functions were obtained employing the catalyst with 1 wt.% of iridium and 0.7–0.8 wt.% of platinum; the optimal ratio between mass of catalyst and mole of tetralin was 17–19 g/mol and temperature between 200 and 220 ◦CItem Vanadium and titanium oxide supported on mesoporous CMK-3 as new catalysts for oxidative desulfurization.(Univesidsad Tecnológica Nacional., 2016) Rivoira , Lorena Paola; Juárez , Juliana María; Falcón , Horacio; Gómez Costa , Marcos Bruno; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Juárez , Juliana MaríaVanadium supported-CMK-3 catalysts with vanadium loading of 1–7 wt.% were studied in the oxidative desulfurization (ODS) of dibenzothiophene as a model sulfur compound. The activity was compared with titanium supported-CMK-3. Structural and textural characterization of the catalysts was performed by means of N2 adsorption, XRD, UV–vis–DRS, Raman spectroscopy, XPS, TEM and TPR. The dispersion and the nature of the vanadium species depend on the V loading, so does the catalyst activity. Vanadium supported-CMK-3 with 7 wt.% of vanadium loading 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 short time in mild conditions. Carbon ordered mesoporous CMK-3 with high surface area and high pore volume promotes a very good anchorage of metallic oxides in the carbons framework reaching high active sites distribution and more stable nanoclusters. The reusability of the catalyst indicates that V-CMK-3 is a potential catalyst for the ODS of dibenzothiopheneItem 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 AlejandraTiO2-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.Item 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 PaolaSBA-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).Item Synthesis and characterization of 2D-hexagonal, 3D-hexagonal and cubic mesoporous materials using CTAB and silica gel.(Univesidsad Tecnológica Nacional., 2016) Martínez , María Laura; Falcón, Horacio; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar AlfredoHighly ordered mesoporous materials SBA family (Santa Barbara Amorphous), with symmetry of two-dimen sional (2D)-hexagonal SBA-3, three-dimensional (3D)-hexagonal P63/mmc (SBA-7) and cubic Pm3n (SBA-1) were synthesized by a simple and easy procedure, designed using silica gel as a silicon source, CTAB (cetyltrimethylammonium bromide) as a structure-directing agent, in highly acidic conditions. The effect of the variation of temperature and reaction time allowed us to obtain the optimum condition to prepare SBA-1, SBA-3 and SBA-7 materials. The sodium silicate generated “in situ” by dissolution of the silica gel, at different con centrations of NaOH and the variation of the synthesis temperature and reaction time are the three factors which allow obtaining different SBA phases. Thus, the best SBA-3, SBA-1 and SBA-7 materials with well-ordered meso- porous system can be obtained in the range of 0.8, 0.9 and 1.0 NaOH concentration and 30 and 25 °C and 45, 2880, 1440 min (for SBA-3, SBA-1 and SBA-7 respectively)Item Vanadium oxide supported on mesoporous SBA-15 modified with AI and Ga as a highly active catalyst in the ODS of DBT.(Univesidsad Tecnológica Nacional., 2016) Rivoira , Lorena Paola; Martínez , María Laura; Anunziata , Oscar Alfredo; 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 dibenzothiopheneItem Estudio experimental y modelado del flujo hidráulico en suelos limo-bentoníticos compactados para su uso en barreras naturales(Revista de Geología Aplicada a la Ingeniería y al Ambiente, 2015) Alercia Biga, Carolina; Eberhardt, Marcelo G.; Arrúa , Pedro A.; Aiassa Martínez, Gonzalo MartínLos suelos loéssicos de Córdoba, presentan una estructura macroporosa y un marcado comportamiento inestable en presencia del agua. Esta característica estructural, los vuelve vulnerables en los procesos de conducción y transporte de agentes externos bajo fenómenos de infiltración. Su mejoramiento mediante el empleo y adición de materiales naturales como la motmorillonita sódica, hace posible su uso como barreras naturales de baja permeabilidad acorde a lo reglamentado por los organismos internacionales. De esta forma, se logra la disminución de su valor de conductividad hidráulica lo cual permite su empleo en la construcción de depósitos de rellenos sanitarios. En este trabajo, se presentan resultados de infiltración en muestras remoldeadas de suelo local con adición de bentonita sódica en diferentes porcentajes, moldeadas con diferentes valores de densidad de compactación. Se analizó el comportamiento hidráulico mediante el uso de un equipo de permeabilidad a pared flexible y se ha establecido el ascenso capilar. Los resultados indican que es posible la disminución de la infiltración de un fluido permeante a través del medio poroso, mediante el incremento de la densidad natural del suelo optimizada mediante procesos mecánicos en conjunto con la incorporación de bentonita. Se observó una respuesta experimental no lineal en las curvas de infiltración obtenidas en diferentes mezclas mejoradas con adición de bentonita. Este comportamiento de características variables, en función del tiempo y de la presencia de adición incorporada, permitió establecer los parámetros necesarios para calibrar el modelo de infiltración propuesto.