Facultad Regional Córdoba
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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 Direct synthesis of ordered mesoporous carbon applied in hydrogen storage(Springer Science+Business Media, 2018) Juárez, Juliana María; Gómez Costa , Marcos Bruno; Anunziata, Oscar AlfredoIn this work, we present a direct, novel and low cost method for the preparation of an ordered mesoporous carbon (OMC). OMC was successfully synthesized by the carbonization of the silica/triblock copolymer/sucrose composite in the presence of sulfuric acid. The resulting material was characterized by XRD, N2 sorption analysis and TEM techniques. The novel synthesis technique improved significantly the H2 storage properties (3.78 wt%) compared with that of CMK-3 synthesized using the nanocasting strategy (2.2 wt%) at 77 K and 10 bar.Item Influence of vanadium nanoclusters in hydrogen uptake using hybrid nanostructured materials(Springer Science+Business Media, 2018) Juárez, Juliana María; Gómez Costa , Marcos Bruno; Martínez, María Laura; Anunziata, Oscar AlfredoIn this work, we report the synthesis and characterization of vanadium oxide nanoclusters (V2O5) supported in silica nano- structured material (SBA-15) and nanostructured carbon (CMK-3). This material is promising in hydrogen adsorption and storage application for energy harvesting. The materials with vanadium oxide nanoclusters (VxOy-SBA-15 and VxOy-CMK-3) were successfully synthesized and characterized by X-ray diffraction, textural properties, UV–Vis-DRS, X-ray photoelec- tron spectroscopy, temperature programmed reduction and transmission electron microscopy analyses. VxOy-SBA-15 and VxOy-CMK-3 improved significantly the H2 storage behavior (1.33 wt% and 3.43 wt% at 77 K and 10 bar) compared with their respective supports SBA-15 and CMK-3. The materials synthesized are promising in hydrogen uptake by weak link forces (physisorption). A mechanism of hydrogen adsorption was proposed and V5+ cation roll in hydrogen uptake was discussedItem Síntesis y caracterización del material nanoestructurado Fe-CMK-3 utilizado en almacenamiento de hidrógeno(Sociedad Argentina de Catálisis, 2019) Venosta, Lisandro F.; Juárez, Juliana María; Gómez Costa , Marcos Bruno; Anunziata, Oscar AlfredoEn este trabajo, informamos la síntesis y caracterización de nanoclusters de óxido de hierro soportados en el carbón nanoestructurado (CMK-3). Este material es prometedor en la aplicación de almacenamiento y adsorción de hidrógeno para almacenamiento de energía. Los materiales con nanoclusters de óxido de hierro (Fe-CMK-3) se sintetizaron exitosamente y se caracterizaron mediante difracción de rayos X, propiedades texturales y análisis de microscopía electrónica de transmisión. La incorporación de oxidos de hierro mejoró significativamente el comportamiento de almacenamiento de H2 (4,45% en peso a 77K y 10 bar) en comparación con su respectivo soporte (CMK-3). El material sintetizado es prometedor en la adsorción de hidrógeno por fuerzas de enlace débil (fisisorción). Se propuso un mecanismo de adsorción de hidrógeno y los nanoclusters de óxido de Fe en fase de magnetita tienen un rol importante en la absorción de hidrógeno.Item Fe-CMK-3 nanostructured material applied in hydrogen uptake J.(Catalysis Society of Australia, 2019) Juárez, Juliana María; Gómez Costa , Marcos Bruno; Anunziata, Oscar AlfredoAll over the world in the past decades, one of the most concerning subjects has been fossil fuel reduction, along with the global warming issue. These concerns have made hydrogen an ideal alternative to conventional fossil-fuel resources. Nevertheless, it has serious disadvantages, such as low volumetric and gravimetric densities that limit its storage [1]. One kind of OMC involves the carbon mesostructured from Korea (CMK). CMK-3 was chosen as a support material for hydrogen storage due to its large surface area, high chemical stability, uniform pore diameter, accessible porosity and three-dimensional conducting network [2]. Metal particles dispersed in the porosity of active carbons are largely contributing to enhanced storage abilities. In this work we studied the influence of the incorporation of iron nanoparticles inside the channels of CMK-3. This could help and make it possible storing hydrogen in carbon and silica matrix but with another mechanism, with a better reversibility improving hydrogen adsorption/desorption behavior.Item Nanoclusters of iron oxice included in CMK-3mesoporous carbon use as hydrogen storage material(Materials Research Society, 2019) Juárez, Juliana María; Venosta, Lisandro F.; Gómez Costa , Marcos Bruno; Anunziata, Oscar AlfredoIn this work we studied the influence of the incorporation of iron oxide nanoparticles inside the channels of the nanostructured mesoporous carbon CMK-3. This research includes synthesis of the mesoporous silicate and synthesis of CMK-3 by nanocasting strategy, incorporation of the iron oxide nanoclusters by wetness impregnation, characterization of these nanomaterials by XRD, N2 adsorption, XPS, and TEM, and study of the improvement in hydrogen adsorption. This material is promising in hydrogen adsorption and storage application for energy harvesting. According to XRD studies, the incorporation of oxide nanoclusters does not compromise the overall structure of the mesoporous carbon CMK-3. In the wide angle region it has been found typical reflections of iron oxide corresponding to the magnetite phase (Fe2+Fe3+ 2 O4). The modified sample Fe-CMK-3 reveal a reduced specific surface area and smaller pore diameter compared to pristine CMK-3 which involves the formation of magnetite nanoparticles within the mesoporous channels of CMK-3. TEM images of Fe-CMK-3 presents metallic oxide nanoparticles well dispersed. The incorporation of iron oxide nanoparticles improved significantly the H2 storage behavior (4.45% wt at 77K and 10 bar) compared to its respective support (CMK-3). Magnetite nanoclusters increased the capacity of hydrogen adsorption in pristine materials. Supposing that weakly orbital interactions occur between H2 and the metal nanocluster, physisorption is the main interaction, all cases have the potential to uptake H2 weakly as physisorption process and the last interaction achieves sufficiently strong energies to store more hydrogen to reach the level adsorption in Fe-CMK-3. In addition, no hydrogen chemisorption was detected. The materials synthesized are promising in hydrogen uptake by weak link forces (physisorption).Item Ordered mesoporous carbons (OMC) type CMK-3 modified with Vandium for improvement H2 storage(Diamond and Carbon Conference Organization, 2018) Juárez, Juliana María; Gómez Costa , Marcos Bruno; Martínez, María Laura; Anunziata, Oscar Alfredo; Martínez, María LauraSome previous studies probed that H2 adsorption can be improved for mesoporous carbons introducing into the framework of the nanomaterial some metals or oxides, like platinum, Zn, ZnO, Ni, NiO, or TiO2. Some other authors have made several efforts in the same direction, for instance, incorporated iron and copper nanoparticles into multiwalled carbon nanotubes and studied their hydrogen adsorption. In this work we studied the influence of the incorporation of vanadium nanoparticles inside the channels of mesoporous carbon CMK-3. This research includes the synthesis of the mesoporous silicate, (hard Template) and the synthesis of the CMK-3 by nanocasting strategy and the incorporation of the vanadium nanoclusters by wetness impregnation. This kind of materials are synthesize by nanocasting strategy using mesoporous silicates as templates and have high surface area (from 1000 to 2000 m2/g) and pore volumes in the range of 0.5 to 1 ml.g-1. Accordingly, CMK-3 was chosen as a support material for hydrogen storage due to its large surface area, high chemical stability, uniform pore diameter, accessible porosity and threedimensional conducting network. The characterization of these nanomaterials was obtained by XRD, N2 adsorption, XPS, TPR and Uv-Vis, TEM, and finally the study of the improvement in the hydrogen adsorption. V5+ cation in V2O5 is an active species to uptake and store hydrogen by a physisorption process and the support plays an important role in metal cluster dispersion and size.Item Aniline alkylation with methanol: relationship nature and strength of active sites - catalytic activity(Materials Chemistry, 2019) Juárez, Juliana María; Anunziata, Oscar AlfredoThe products of the alkylation of aniline (A) with methanol (M), both carbon alkylate and N-derivatives are important intermediaries in the organic synthesis. Thus, toluidine (To), N-methylaniline (NMA) and N-dimethylaniline (NNDMA), the main products of this reaction are used as intermediates in the manufacture of dyes, plastics and explosives. The preparation of these products in liquid phase has been widely studied. Naturally, this process in the presence of strong acids generates problems of corrosion and contaminating residues. A comparative analysis between all the reaction products obtained indicates that NMA is the initial product of aniline alkylation with methanol with the highest formation rate. The NNDMA would come from the alkylation of the NMA following a relatively similar behavior. NNDMT follows a particular behavior. It is always secondarily unstable except in SBS-SLS (Strong Bonsted - Strong Lewis site pairs), where it is stable at high conversion levels. To is always an unstable secondary product, except for the SBS-SBS (stable) group, with a maximum formation rate in SBS-SLS between 15-20% of aniline conversion and more than 20% in the neighboring SBS-SBS.Item Influencia de nanoclusters de óxido de vanadio dispersos en materiales nanoestructurados híbridos en el almacenamiento de hidrógeno(RITEQ, 2018) Juárez, Juliana María; Gómez Costa , Marcos Bruno; Martínez, María Laura; Anunziata, Oscar AlfredoEn todo el mundo en las últimas décadas, uno de los temas más preocupantes ha sido la reducción de los combustibles fósiles, junto con el problema del calentamiento global. Estas preocupaciones han convertido al hidrógeno en una alternativa ideal a los recursos fósiles convencionales. Un tipo de OMC, el carbón mesoestructurado de Corea (CMK), se sintetiza mediante la estrategia de nanocasting utilizando silicatos mesoporosos como plantillas; tiene un área superficial alta (de 1000 a 2000 m2 / g) y un volumen de poro en el rango de 0.5 a 1 ml.g-1. Por consiguiente, se eligió el CMK-3 como material de soporte para el almacenamiento de hidrógeno debido a su gran área superficial, alta estabilidad química, diámetro de poro uniforme, porosidad accesible y red tridimensional [Yang et al. (2005), Anbia et al. (2009), Anbia et al. (2011)]. Por otro lado, el material mesoporoso silíceo, SBA-15 muestra redes regulares y un diámetro de poro que fluctúa de 1.5 a 10 nm dependiendo del agente plantilla utilizado en su síntesis. Debido a su tamaño y forma de poros, es un material adecuado como absorbente para una variedad de gases y vapores [Schmidt et al. (1995), Soler-Illia (2002)]. En este trabajo estudiamos la influencia de la incorporación de nanopartículas de vanadio dentro de los canales de dos soportes diferentes, el silicato mesoporoso SBA-15 y el carbón mesoporoso CMK-3. Esta investigación incluye la síntesis del silicato mesoporoso y la síntesis de CMK-3 mediante la estrategia de nanocasting, la incorporación de nanoclusters de vanadio por impregnación de humedad, la caracterización de estos nanomateriales por XRD, adsorción de N2, XPS, TPR y UV-Vis, TEM y el estudio de la mejora en la adsorción de hidrógenoItem Drug release system. Nanostructured Ketorolactromethamine/MCF composite(CICAT, 2018) Cussa , Jorgelina; Juárez, Juliana María; Prados, Antonela M.; Gómez Costa , Marcos Bruno; Anunziata, Oscar AlfredoLos sistemas controlados de administración de fármacos mantienen la concentración de medicamentos en los lugares específicos del cuerpo, mejorando la eficacia terapéutica y reduciendo la toxicidad. El material de espuma celular mesoestructurada (MCF) es un nuevo y prometedor huésped para los sistemas de administración de fármacos debido a su alta biocompatibilidad, biodegradabilidad in vivo y baja toxicidad. El composite Ketorolaco-Tromethamine/MCF fue sintetizado. La síntesis de material y la carga de ketorolacotrometamina en los poros de MCF fueron exitosas, demostrándose mediante XRD, FTIR, TGA, TEM y análisis de textura. Obtuvimos resultados prometedores para la liberación controlada de fármacos utilizando el nuevo material MCF. La aplicación de estos materiales en la liberación de KETO es innovadora, logrando una alta velocidad inicial y luego manteniendo una velocidad constante en tiempos altos. Esto permite mantener la concentración del fármaco dentro del rango de eficacia terapéutica, siendo altamente aplicable para el tratamiento de enfermedades que necesitan una respuesta rápida. La liberación de KETO/MCF se comparó con otro soporte de KETO (KETO / SBA-15) y tabletas comerciales.