Browsing by Author "Rivoira, Lorena Paola"

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Activated carbons synthetized from orange peel to produce clean energy
(2022) Rivoira, Lorena Paola; Gómez Costa, Marcos Bruno; Ledesma, Brenda Cecilia; Beltramone, Andrea Raquel
As we all know, a clean energy revolution is taking place all over the world in pursuit of replacing oil. The present work stands out an environmental point of view by proposing biomass wastes from different industrial areas to produce not only a biofuel but also as raw material to synthetize the catalyst involved in the HDO reaction. In this way the process ceases to rely on the antiquated and obsolete linear economy where products, services, wastes, materials, water and energy have a beginning and an end to become a process with greater tendency to the modern circular economy, closely related to the idea of sustainability. Products, materials and resources are expected to last as long as possible while minimizing waste as much as possible too. Agricultural and forestry waste are available everywhere being a low cost raw material and it is possible to provide added value to the organic wastes of small and medium size enterprises. The hydrodeoxygenation (HDO) of guaiacol has been performed in a batch reactor under 12 atm of H2 and different temperatures over activated carbon synthetized from orange peel discarded from juice industry. Carbon activation was carried out through a chemical process with phosphoric acid as an activating agent, varying the acid concentration, the ratio substrate/activating agent and time of contact between them. The best support was obtained using carbonization time of 1 h, temperature of carbonization of 470oC, phosphoric acid concentration of 50 wt.% and with BET area of 1429 m2/g. Subsequently, the metallic nanoparticles were deposited in the activated carbon to use the solid as a catalytic material for the hydrodeoxygenation of guaiacol. The catalytic material was modified with metallic nanoparticles of Pt. The catalysts were characterized by means of X-ray diffraction, N2 isotherms, XPS, SEM and TEM. Good structure, narrow pore size distribution and high platinum dispersion were achieved in the synthesized catalysts. The objective of this investigation is the evaluation of the catalytic activity and to compare it with SBA-15 support studied previously. The catalyst presented excellent performance for biofuels generation.
Biomass wastes as a raw material for mesoporous catalyst applied in HDO of guaiacol
(2022) Rivoira, Lorena Paola; Ledesma, Brenda Cecilia; Gómez Costa, Marcos Bruno; Beltramone, Andrea Raquel
As we all know, a clean energy revolution is taking place all over the world in pursuit of replacing oil. The present work stands out an environmental point of view by proposing biomass wastes different industrial areas to produce not only a biofuel but also as raw material to synthetize the catalyst involved in the HDO reaction. In this way the process ceases to rely on the antiquated and obsolete linear economy where products, services, wastes, materials, water and energy have a beginning and an end to become a process with greater tendency to the modern circular economy, closely related to the idea of sustainability. Products, materials and resources are expected to last as long as possible while minimizing waste as much as possible too. Agricultural and forestry waste are available everywhere being a low cost raw material and it is possible to provide added value to the organic wastes of small and medium size enterprises. The hydrodeoxygenation (HDO) of guaiacol has been performed in a batch reactor under 12 atm of H2 and different temperatures over activated carbon synthetized orange peel discarded juice industry. Carbon activation was carried out through a chemical process with phosphoric acid as an activating agent, varying the acid concentration, the ratio substrate/activating agent and time of contact between them. The best support was obtained using carbonization time of 1 h, temperature of carbonization of 470oC, phosphoric acid concentration of 50 wt.% and with BET area of 1429 m2/g. Subsequently, the metallic nanoparticles were deposited in the activated carbon to use the solid as a catalytic material for the hydrodeoxygenation of guaiacol. The catalytic material was modified with metallic nanoparticles of Pt. The catalysts were characterized by means of X-ray diffraction, N2 isotherms, XPS, SEM and TEM. Good structure, narrow pore size distribution and high platinum dispersion were achieved in the synthesized catalysts. The objective of this investigation is the evaluation of the catalytic activity and to compare it with SBA-15 support studied previously. The catalyst presented excellent performance for biofuels generation.
Catalytic oxidation of sulfur compounds over Ce-SBA-15 and Ce-Zr-SBA-15
(2021) Rivoira, Lorena Paola; Vallés, Verónica Alejandra; Martínez, María Laura; Yanika, Sa-ngasaeng; Siriporn, Jongpatiwut
The catalytic oXidation of different sulfur compounds, commonly present in liquid fuel, was studied over a series of ceria and ceria-zirconium based oXidation mesoporous catalysts. SBA-15 was synthesized using sol-gel method and Ce and Ce-Zr were added by two different procedures: i) directly during the synthesis and ii) via post- synthesis method. The catalysts were characterized by XRD, N2 adsorption isotherms, XPS, DRUV-Vis, TEM, SEM and Py-FTIR. Low angle XRD, N2 isotherms and TEM confirmed that the structure was not changed after metal incorporation. Wide angle XRD, UV–vis-DRS, XPS and TEM determined that the catalysts prepared by direct synthesis presented higher dispersion of Ce oXides, smaller particle size and isolated Zr4+ species. FTIR of adsorbed/desorbed pyridine indicated that zirconium as promoter increases the Lewis acidity of the catalysts, especially during direct synthesis. Ce-Zr-SBA-15 catalyst prepared by direct synthesis was very active in the oXidation of dibenzothiophene, 4,6-dimethyl dibenzothiophene and benzothiophene using hydrogen peroXide (H2O2) as oXidant agent and acetonitrile as polar solvent. The effect of acidity in the catalyst, hydrogen peroXide concentration and temperature was studied. The deactivation test demonstrated that the catalyst is stable and adequate for the industrial process.
Desulfuración oxidativa utilizando material mesoporoso Ti-SBA-16
(2014) Rivoira, Lorena Paola; Vallés, Verónica; Ledesma, Brenda; Martínez, María Laura; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
La oxidación de compuestos organosulfurados conduce a la formación de los sulfóxidos/sulfonas correspondientes, lo que permite que sean fácilmente removidos mediante extracción en solventes polares o por adsorción. El proceso de ODS es llevado a cabo bajo condiciones muy suaves, comparado con el proceso convencional de HDS. El objetivo del presente trabajo es estudiar el efecto del método de preparación de SBA-16 modificada con titanio en el rendimiento de la ODS del DBT con H2O2 y acetonitrilo como solvente en condiciones suaves de reacción. Se estudiaron dos materiales TiO2-SBA-16 obtenido por impregnación húmeda y Ti-SBA-16 obtenido mediante síntesis directa. con una relación de Si/Ti=20. Para la actividad catalítica se lleva a cabo la reacción de oxidación a 70°C y presión atmosférica se utilizó un reactor batch. Se utilizó H2O2 como agente oxidante y acetonitrilo como solvente.
Eliminación de azufre mediante desulfuración oxidativa con SBA-16 modificada con titanio
(2014) Rivoira, Lorena Paola; Vallés, Verónica; Ledesma, Brenda; Martínez, María Laura; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
La oxidación de compuestos organosulfurados conduce a la formación de los sulfóxidos/sulfonas correspondientes, los cuales son mucho más polares, lo que permite que sean fácilmente removidos mediante extracción en solventes polares o por adsorción. El proceso de ODS es llevado a cabo bajo condiciones muy suaves (presión atmosférica y 60-90ºC), comparado con el proceso convencional de HDS, donde comúnmente son usadas presiones mayores a los 30 bar y temperaturas desde los 300 a los 380ºC. Resultados recientes muestran que tamices moleculares que contienen Ti exhiben buena reactividad catalítica en la oxidación de sulfuro, mercaptano, tiofeno y derivados (1). El objetivo del presente trabajo es estudiar el efecto del método de preparación de SBA-16 modificada con titanio (características de las especies activas de Ti y/o TiO2) en el rendimiento de la ODS del DBT con H2O2 y acetonitrilo como solvente en condiciones suaves de reacción.
EXperimental design optimization of the ODS of DBT using vanadium oXide supported on mesoporous Ga-SBA-15
(2020) Rivoira, Lorena Paola; Cussa, Jorgelina; Martínez, María Laura; Beltramone, Andrea Raquel
EXperiment design-response surface methodology is applied in this work to model and optimize the o Xidation of dibenzothiophene (DBT) using VOX-Ga-SBA-15 catalyst. The analyzed variables are the influence of the nature of the catalyst (V and Ga loading), the s ubstrate/catalyst mass ratio (g DBT/g of catalyst) and the o Xidant/substrate molar ratio (H2O2/DBT). The response analyzed is conversion of DBT at 15 min of reaction time. A set of re- sponse surfaces were obtained applying the BoX-Behnken Design. Based on statistical methodology it was pos- sible to find the best arrangement between the amounts of the gallium heteroatom and the vanadium active species. The higher levels of the objective function were obtained employing the catalyst with 4 wt.% of gallium and 6 wt.% of vanadium; the optimal ratio between g DBT/g of catalyst was 4 and the molar ratio between H2O2/DBT was 5. Gallium incorporation as heteroatom in tetrahedral position allowed the better anchorage ofthe active species of vanadium, generating a very well dispersed catalyst. The optimized catalyst minimized the mass transfer limitation and moreover, was active after several recycles. The best catalyst was likewise very active for the oXidation of the most refractory sulfur compounds as benzothiophene and 4,6-dimetyldi- benzothiopene.
Experimental desing optimization of the ods of DBT using V2O5 supported on GA-SBA-15.
(Univesidsad Tecnológica Nacional, 2017) Rivoira, Lorena Paola; Cussa, jorgelina; Martínez , María Laura; Beltramone, Andrea Raquel; Martínez , María; Cussa, jorgelina
Experiment design-response surface methodology (RSM) was used in this work to model and optimize one response in the oxidative desulfurization of dibenzothiophene with hydrogen peroxide using VOx-Ga-SBA-15 catalysts with different Ga/Si and V/Si ratios. In this study, we analyze the influence of the nature of the catalyst (metal/Si ratio), the catalyst/substrate ratio and the oxidant/substrate ratio as factors for the design. The response analyzed was conversion at 15 min 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 objective function were obtained employing the catalyst with Ga/Si and V/Si ratios of 1/15 and 1/25, respectively. 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 depended on the vanadium loading and on the nature of the support.
Hidrogenación de tetralin en presencia de quinolina sobre Ir/SBA-16 modificada con titanio
(2014) Ledesma, Brenda; Vallés, Verónica; Rivoira, Lorena Paola; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
En el presente trabajo informamos resultados de la hidrogenación efectiva de tetralin en presencia de quinolina, en condiciones menos severas que las industriales; para lo cual desarrollamos un nuevo material catalítico mesoporoso Ir/SBA-16 modificado con titanio. La incorporación de Ti facilitó la mayor y mejor homogeneidad en la dispersión de partículas de Ir metálico (Ir0). Para conocer el efecto en la dispersión del metal de transición (1), el Ti fue incorporado vía post síntesis como TiO2 y en red empleando el método sol-gel obteniendo así los catalizadores Ir/TiO2-SBA-16 e Ir/Ti-SBA-16.
Hidrogenación de tetralin utilizando un catalizador bifuncional de iridio/platino-SBA-15
(2014) Vallés, Verónica; Ledesma, Brenda; Rivoira, Lorena Paola; Cussa, Jorgelina; Martínez, María Laura; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
Los catalizadores bimetálicos de Pt–Pd han recibido considerable atención debido a que demuestran tener una alta actividad en una amplia variedad de aplicaciones catalíticas (1). Con alta actividad, selectividad y estabilidad, comparada con catalizadores monometálicos de Pt y Pd. Por ejemplo, catalizadores bimetálicos Pt-Pd muestran tener mayor resistencia frente a envenenamientos en comparación con catalizadores de Pt (2-4). Las características estudiadas del catalizador serán correlacionadas con su performance catalítica en la hidrogenación del tetralin. El objetivo final es encontrar la proporción óptima de cada uno de los metales de forma de lograr la mayor actividad en dicho proceso.
Hidrogenación de tetralin utilizando un catalizador bifuncional de iridio/platino-SBA-15.
(Univesidsad Tecnológica Nacional, 2014) Vallés , Verónica Alejandra; Ledesma, Brenda Cecilia; Rivoira, Lorena Paola; Cussa , jorgelina; Martínez , María Laura; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Martínez , María; Cussa , jorgelina; Ledesma, Brenda
Los catalizadores bimetálicos de Pt–Pd han recibido considerable atención debido a que demuestran tener una alta actividad en una amplia variedad de aplicaciones catalíticas (1). Con alta actividad, selectividad y estabilidad, comparada con catalizadores monometálicos de Pt y Pd. Por ejemplo, catalizadores bimetálicos Pt-Pd muestran tener mayor resistencia frente a envenenamientos en comparación con catalizadores de Pt (2-4). Las características estudiadas del catalizador serán correlacionadas con su performance catalítica en la hidrogenación del tetralin. El objetivo final es encontrar la proporción óptima de cada uno de los metales de forma de lograr la mayor actividad en dicho proceso.
Hydrogenation of tetralin over Ir catalysts supported on titania-modified SBA-16
(2014) Ledesma, Brenda; Vallés, Verónica; Rivoira, Lorena Paola; Martínez, María Laura; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
Abstract A series of Ti modified SBA-16 supports and their respective Ir-catalysts were prepared and character- ized to study the effect of support preparation method on the dispersion of iridium and on the characteristics of Ir surface species. Two methods of incorporation of titania were tested: the sol–gel method in order to obtain Ti as heteroatom and incipient wetness impregnation to obtain Ti as TiO2 (anatase phase). The results show that supports with different Ti species and dispersion can be obtained. The final catalyst was characterized at different preparation stages by XRD, elemental analysis and BET. The presence of Ti as Ti4? in the nanostructure of SBA and as TiO2 (anatase phase) was analyzed by UV–Vis–DRS and Raman spectroscopy. The iridium oxidation sate upon Ti-con- taining SBA-16 was studied by XPS, EDX, TEM and XRD, arriving at the good proportion of Ir0. H2 chemi- sorption and TEM characterization for Ti-SBA-16 indi- cated that Ir particle size was lower than anatase/SBA-16. The catalyst that we synthesized had good activity mea- sured in tetralin hydrogenation in presence of quinoline at mild conditions. The experimental data were quantitatively represented by a modified Langmuir–Hinshelwood-type rate equation. The preliminary results show these materials as promising catalysts for HDS/HDN reactions.
Ir-Pt/SBA-15 applied in the optimization of tetralin hydrogenation.
(Univesidsad Tecnológica Nacional, 2015) Vallés , Verónica Alejandra; Ledesma , Brenda Cecilia; Rivoira, Lorena Paola; Cussa , jorgelina; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Cussa , jorgelina; Ledesma , Brenda
Bimetallic catalysts have received considerable attention for hydrotreating (HDT) because they show high activity. The features of the catalysts here studied are going to be correlated with their catalytic performance in the hydrogenation of tetralin at mild conditions. The final goal is to find the optimal proportion of each metal in order to be more active and the best reaction conditions (temperature and amount of catalyst). The statistical experiments design is the process of planning an experiment to obtain appropriate data that can be analyzed by statistical methods, to produce concrete and valid conclusions. One of the main advantages in the response curve is to visualize the response for all levels of the experimental factors Experiment design response surface methodology (RSM) is used in this work to model and to optimize the process. Platinum and Iridium nanoparticles were incorporated into SBA-15 support by the wet co-impregnation method. Ir content was set as 1wt. % and Pt was varied from 0 to 1wt. %. The catalysts were characterized by XRD, BET, XPS, TEM, ICP and TPR. XRD profiles are characteristic of the two-dimensional p6mm hexagonal mesostructure with d100 spacing of 10.16 nm; where the d100 spacing upon Ir and Pt incorporation were quite similar to pristine SBA-15. The TEM images and XPS demonstrate that the metal particles were mainly present inside the porous and XPS and TPR corroborated the reduced state of the metals. The catalytic activity was measured in a 4563Parr reactor at 15 atm of hydrogen and 360 rpm. Feed consisted in 50 mL of tetralin in Dodecane, the amount of tetralin is set according to the ratio of catalyst mass/mass reagent corresponding to each reaction. The application of this methodology allows a better understanding of the influence of the different factors: content of metal on catalyst (A), relationship: mass of catalyst/reagent mass (B) and reaction temperature (C), on two responses: conversion at 3 h and at 5 h of reaction time. These factors were carefully selected taking account the influence of the parameters in the reaction. The design was analyzed by Statgraphics and Statistica Soft. We found that, the variable Catalyst has the best influence over the Conversion at the 95.0% confidence level, according to the Pareto.
Iron-modified mesoporous materials as catalysts for ODS of sulfur compounds
(2020) Rivoira, Lorena Paola; Juárez, Juliana María; Martínez, María Laura; Beltramone, Andrea Raquel
Fe-modified mesoporous catalysts were used in the ODS of DBTs using H2O2 as oXidant and acetonitrile as solvent. SBA-15, MCM-48, CMK-3 and CMK-1 were used as supports. Iron was incorporated using iron nitrate by wetness impregnation. The catalysts were characterized by XRD, N2 isotherms, TEM, XPS and ICP. We developed catalysts with high specific surface area, pore volume and narrow mesopore size distribution and highly dis- persed Fe- species. The catalysts were tested in the o Xidative desulfurization of different sulfur compounds as benzothiophene, dibenzothiopene and 4,6-dimethyl dibenzothiopene. The catalyst prepared using CMK-3 as support was the most active for the ODS reaction. The good activity was related with the high dispersion of the iron oXides, mainly in the magnetite phase. Temperature, hydrogen peroXide and sulfur initial concentration were studied using Fe-CMK-3 in the oXidation of DBT. The optimal operation conditions were determined. Fe- CMK-3 is an active and stable catalyst to be applied in the industrial process of ODS.
Material catalitico Ir/Ti-SBA-16 para la hidrogenación de tetralin
(2014) Ledesma, Brenda; Vallés, Verónica; Rivoira, Lorena Paola; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
En el presente trabajo informamos resultados de la hidrogenación efectiva de tetralín en presencia de quinolina, en condiciones menos severas que las industriales; para lo cual desarrollamos un nuevo material catalítico mesoporoso Ir/SBA-16 modificado con titanio. La incorporación de Ti facilitó la mayor y mejor homogeneidad en la dispersión de partículas de Ir metálico (Ir0). Para conocer el efecto en la dispersión del metal de transición, el Ti fue incorporado: 1) vía post síntesis como TiO2: Se realiza un secado previo del material SBA-16, luego, 0,5 g. de la muestra seca se dispersó en una solución que contenía 2ml de Tetrabutilortotitanato (TTBT) y 5 ml de etanol, y 2) en red empleando el método de síntesis sol-gel: se parte de una síntesis de SBA-16 ya publicada y luego de incorporar el TEOS, a continuación se gotea Tetraetilortotitanato (TEOT) disuelto previamente en etanol.
New catalyst source applied in biofuel manufacturing
(2020) Rivoira, Lorena Paola; Ledesma, Brenda Cecilia; Gómez Costa, Marcos Bruno; Beltramone, Andrea Raquel
A clean energy revolution is taking place all over the world in pursuit of replacing oil. This work stands out an environmental point of view by proposing biomass wastes from different industrial areas to produce not only a biofuel but also as raw material to synthetize the catalyst involved in the HDO reaction. In this way the process ceases to rely on the antiquated and obsolete linear economy where products, services, wastes, materials, water and energy have a beginning and an end to become a process with greater tendency to the modern circular economy, closely related to the idea of sustainability. Products, materials and resources are expected to last as long as possible while minimizing waste as much as possible too. Agricultural and forestry waste are available everywhere being a low cost raw material and it is possible to provide added value to the organic wastes of small and medium size enterprises. The hydrodeoxygenation (HDO) of guaiacol has been performed in a batch reactor under 12 atm of H2 and different temperatures over activated carbon synthetized from orange peel discarded from juice industry. Carbon activation was carried out through a chemical process with phosphoric acid as an activating agent, varying the acid concentration, the ratio substrate/activating agent and time of contact between them. The best support was obtained using carbonization time of 1 h, temperature of carbonization of 470oC, phosphoric acid concentration of 50 wt.% and with BET area of 1429 m2/g. Subsequently, the metallic nanoparticles were deposited in the activated carbon to use the solid as a catalytic material for the hydrodeoxygenation of guaiacol. The catalytic material was modified with metallic nanoparticles of Pt. The catalysts were characterized by means of X-ray diffraction, N2 isotherms, XPS, SEM and TEM. Good structure, narrow pore size distribution and high platinum dispersion were achieved in the synthesized catalysts. The objective of this investigation is the evaluation of the catalytic activity and to compare it with SBA-15 support studied previously. The catalyst presented excellent performance for biofuels generation.
Optimization of the synthesis of SBA-3 mesoporous materials by experimental design
(Elsevier Inc., 2016-02-18) Ponte, María Virignia; Rivoira, Lorena Paola; Cussa, Jorgelina; Martínez, Maria Laura; Beltramone, Andrea Raquel; Anunziata, Oscar Alfredo
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).
Síntesis y caracterización de un catalizador soportado iridio/platino-SBA-15 para su aplicación
(2014) Vallés, Verónica; Ledesma, Brenda; Rivoira, Lorena Paola; Cussa, Jorgelina; Martínez, María Laura; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
En el presente trabajo se estudió el efecto de la dispersión de metales nobles Ir y Pt y la interacción con el soporte SBA-15, relacionándolos con la actividad catalítica del catalizador en la reacción de hidrogenación del Tetralin utilizando un reactor Parr a 250°C y 15 atm. Con este objetivo se sintetizaron catalizadores Ir/Pt-SBA-15 modificados con distintos % de Ir y Pt. La mesoestructura del soporte SBA-15 le confiere una estabilidad térmica relativamente alta y el diámetro apropiado de poro permite convertir moléculas voluminosas como las presentes en los cortes de combustibles líquidos. El soporte fue preparado por el método de sol-gel. Para la obtencion del sitio catalitico se utilizó l método de impregnación incipiente. Se disuelven el Acetil acetonato de Iridio (IrAcAc) y el Acido cloroplatinico hidratado (H2PtCl6.H2O) en 50 ml de etanol a 50ºC con reflujo. Luego se agrega a la SBA-15 previamente pesada la solución y se lo lleva a un evaporador rotatorio a 60 ºC y 70 rpm hasta lograr evaporar todo el solvente. Luego se deja secando en estufa a 110 ºC por 24 h. Posteriormente es calcinado en mufla a 500 ºC por 5 horas, seguido de reducción con hidrógeno. El material fue caracterizado mediante difracción de rayos X (XRD), se puede observar que conserva la estructura mesoporosa a bajo ángulo, mientras que a alto ángulo se observan los índices de refracción característicos de Ir y Pt metálicos. También fueron caracterizados por XPS y TEM. La dispersión del Me fue calculada mediante quimisorción de H2 se obtuvieron partículas de iridio/Platino (d= 4,0-2.0 nm) homogéneamente disperso, con una dispersión de más del 60%. Se obtuvo una
Syntesis, characterization and hydrotreating catalitic performance of Ir/Ti-SBA-16 and Ir/TIO2-SBA-16.
(2014) Ledesma, Brenda; Vallés, Verónica; Rivoira, Lorena Paola; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
A series of Ti modified SBA-16 supports and their respective Ir-catalysts were prepared, and characterized to study the effect of support preparation method on the dispersion of iridium and on the characteristics of Ir surface species, with the main aim of obtaining Nitrogen-tolerant catalysts to be used in second stage processes of mild-hydrotreating. Two methods of titania incorporation were tested: the sol-gel method in order to obtain Ti as heteroatom and incipient wetness impregnation to obtain Ti as TiO2 (anatase phase). The final catalyst was characterized at different stage of preparation by XRD, EDX, TEM, elemental analysis and BET, arriving at the good proportion of Ir0. The presence of Ti as Ti+4 in the nanostructure of SBA and as TiO2 (anatase phase) was analyzed by UV-vis-DRS and Raman spectroscopy. The average metal particle size indicates that the Ir particle size is lower when we used Ti-SBA-16 than anatase/SBA-16. We study the catalytic properties of 1 wt% Ir-containing SBA-16 materials modified with Ti as heteroatom and impregnated with TiO2 (anatase phase), in the hydrogenation of tetralin to decalin in the presence of 100 ppm of N as quinoline at 250°C and 15 atm of pressure of hydrogen, using a Parr reactor. The catalysts synthesized by us had good activity measured in tetralin hydrogenation under mild conditions. The experimental data was quantitatively represented by a modified Langmuir-Hinshelwood type rate equation. The preliminary results show these materials as promising catalysts for HDT and HDN reactions.
Synthesis, characterization and catalytic performance of bimetallic Ir-Pt catalysts for tetralin hydrogenation
(2014) Vallés, Verónica; Ledesma, Brenda; Rivoira, Lorena Paola; Cussa, Jorgelina; Martínez, María Laura; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
Bimetallic Pt–Pd catalysts have received considerable attention, because they show high activity in a variety of catalytic applications (1) and stability compared with monometallic Pt or Pd catalysts. For instance, the bimetallic Pt–Pd catalysts have been shown to have higher resistance toward poisonscompared to Pt catalysts (2-4). For supported bimetallic clusters, the surface and bulk composition strongly depend on a series of parameters, for example, preparation procedures, metal–metal and metal–support interactions. The final goal is to find the optimal proportion of each metal in order to be more active in these processes.In this case a 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 metal showed the best activity measured in tetralin hydrogenation. Platinum (Pt) and Iridium (Ir) nanoparticles were incorporated into SBA-15 support [1-4] by the wet co-impregnation method. The metal precursors were Iridium acetylacetonate and cloroplatinic acid. The samples were calcined at 500°C and previous to the catalytic test the samples were reduced by heating at 2°C/min to 450°C in a H2 stream for 5 h. Hereinafter this catalyst will be referred as Ir-Pt- SBA-15 (x), with x= 1-3. The catalytic activity was measured in a 4563Parr reactor, at 250°C, 15 atm of pressure of hydrogen and 360 rpm for tetralin hydrogenation (feed consisted in 50 mL of 5% v/v of tetralin (98.5% FLUKA) in Dodecane). The Pt-Ir-SBA-15 catalyst with 1 %wt. of each metals had the highest activity measured in tetralin hydrogenation at mild conditions. The good activity was correlated with higher Ir/Pt dispersion on SBA-15 mesostructured material used as support, as we seen by TEM and H2 Chemisorption, with higher active metal sites exposed to reactant. The Ir-Pt-SBA-15 activity is sufficiently high to envisage use in the final stages of a refinery process producing diesel fuel of high Cetane Number by hydrodearomatization.
Synthesis, characterization and hydrotreating activity of Ir catalysts supported on titania-modified mesoporous material
(2014) Ledesma, Brenda; Vallés, Verónica; Rivoira, Lorena Paola; Martínez, María Laura; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
A titanium modified catalyst based on noble metal has been prepared with the main aim of obtaining Nitrogen-tolerant catalysts to be used in second stage processes of mild-hydrotreating. We study the catalytic properties of 1 wt% Ir-containing SBA-16 materials modified with Ti as heteroatom and impregnated with TiO2 (anatase phase), in the hydrogenation of tetralin to decalin in the presence of 100 ppm of N as quinoline at 250°C and 15 atm of pressure of hydrogen, using a Parr reactor. The iridium oxidation sate upon Ti-containing SBA-16 was studied by XPS, EDX, TEM and XRD, arriving at the good proportion of Ir0. The average metal particle size indicate that the Ir particle size is lower when we used Ti-SBA-16 than anatase/SBA-16. The experimental data was quantitatively represented by a modified Langmuir-Hinshelwood type rate equation. The preliminary results show these materials as promising catalysts for HDS/HDN reactions.

Browsing by Author "Rivoira, Lorena Paola"

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