UTN- FRC -Producción Académica de Investigación y Desarrollo

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Start date: 2020Author: search.filters.author.Anunziata, Oscar A.

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Now showing 1 - 10 of 21
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    Nanoscopic hydrogen reservoir orange peel biowaste
    (2022) Juárez, Juliana María; Ledesma, Brenda Cecilia; Anunziata, Oscar A.; Gómez Costa, Marcos Bruno; Beltramone, Andrea Raquel
    This work addresses the bio-waste valorization approach for the development of a novel carbonaceous nanomaterial to be used in the adsorption of hydrogen as an alternative in the use of green hydrogen. In this research, activated carbons were synthesized orange peel using different synthesis conditions. With the activated carbons obtained with the best structure and texture, the adsorption of hydrogen and the effects on their meso / microporosity were studied. The activation of the carbon was carried out by means of a chemical process with phosphoric acid as activating agent, varying the acid concentration, the substrate / activating agent ratio, and the contact time between them. The best support was obtained using a carbonization time of 1 h, a carbonization temperature of 470oC, a phosphoric acid concentration of 50% by weight and a BET area of ??1402 m2 / g. Said material significantly improved H2 storage behaviour compared to CMK-3 type nanostructured carbon (3.1% by weight at -196,15 oC and 10 bar). The synthesized material shows promise in absorbing hydrogen by weak binding forces (physisorption).
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    Sistema de liberación controlada de fármacos: espuma mesoporosa MCF-clorambucilo
    (2022) Juárez, Juliana M.; Cussa, Jorgelina; Anunziata, Oscar A.; Gómez Costa, Marcos Bruno
    La espuma celular mesoestructurada (MCF) es un material prometedor para los sistemas de administración de fármacos dado a la alta biocompatibilidad, biodegradabilidad y baja toxicidad. Sus propiedades incluyen una gran área superficial, poro grande uniforme. En este trabajo, la espuma mesoporosa MCF fue sintetizada con éxito para su aplicación en nanotransportadores de fármacos, específicamente de Clorambucilo, obteniendo el composite MCF-CBL. La síntesis del material mesoporoso y el proceso de incorporación de Clorambucilo en los poros de la MCF fueron exitosos tal como se muestra en los análisis de XRD, FTIR, TEM y análisis de propiedades texturales. La liberación del fármaco se realizó simulando las condiciones fisiológicas para reproducir las condiciones del organismo. Se evaluó el mecanismo de liberación del fármaco en el hospedaje MCF-CLB. Se utilizaron diferentes modelos matemáticos para ajustar los datos experimentales, el mejor modelo que describe el fenómeno en estudio durante todo el período es el modelo de Weibull. Los resultados auspiciosos que obtuvimos para la liberación del fármaco utilizando el nuevo material, la principal ventaja de esta liberación es que la velocidad de liberación es rápida al inicio y luego disminuye gradualmente hasta que se liberan 24 h prácticamente todo el fármaco contenido en el portador. (> 95%).
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    Sistema de liberación controlada de fármacos: espuma mesoporosa MCFClorambucilo
    (2022) Juárez, Juliana María; Cussa, Jorgelina; Gómez Costa, Marcos Bruno; Anunziata, Oscar A.;
    La espuma celular mesoestructurada (MCF) es un material prometedor para los sistemas de administración de fármacos dado a la alta biocompatibilidad, biodegradabilidad y baja toxicidad. Sus propiedades incluyen una gran área superficial, poro grande uniforme. En este trabajo, la espuma mesoporosa MCF fue sintetizada con éxito para su aplicación en nanotransportadores de fármacos, específicamente de Clorambucilo, obteniendo el composite MCFCBL. La síntesis del material mesoporoso y el proceso de incorporación de Clorambucilo en los poros de la MCF fueron exitosos tal como se muestra en los análisis de XRD, FTIR, TEM y análisis de propiedades texturales. La liberación del fármaco se realizó simulando las condiciones fisiológicas para reproducir las condiciones del organismo. Se evaluó el mecanismo de liberación del fármaco en el hospedaje MCFCLB. Se utilizaron diferentes modelos matemáticos para ajustar los datos experimentales, el mejor modelo que describe el fenómeno en estudio durante todo el período es el modelo de Weibull. Los resultados auspiciosos que obtuvimos para la liberación del fármaco utilizando el nuevo material, la principal ventaja de esta liberación es que la velocidad de liberación es rápida al inicio y luego disminuye gradualmente hasta que se liberan 24 h prácticamente todo el fármaco contenido en el portador. (> 95%).
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    HaP / LP-SBA-15 Nanocomposite for efficient removal of fluoride from contaminated wáter
    (2020) López, Claudia G.; Anunziata, Oscar A.; Cussa, Jorgelina
    Hydroxyapatite (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, and applied properly 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.
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    Mesopore carbón starch with acid properties: synthesis and characterization
    (2020) Martínez, María Laura; Anunziata, Oscar A.
    We have shown that a promising material with acidic properties can be successfully prepared from starch mesoporous carbon (SMC), functionalized with sulfated zirconia. The process of assembling P123, starch, zirconia, and silicon synthesized Zr-modified ordered mesoporous carbon. SMC and Zr-SMC were characterized by BET for their texture properties and, using Scanning Electron Microscopy (SEM), their morphology. Acidic properties were acquired by programmed thermodesorption of ammonia (NH3 TPD). These studies show that the Zr-SMCs material is mainly composed of mesopores with an average pore size of approximately 3.5 nm, high surface area and pore volume, and has medium to strong acidity properties.
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    Super-acid sulfated/zirconium-containig nanostructured carbons
    (2020) Martínez, María Laura; Anunziata, Oscar A.
    In this work, we report the successful preparation of a superacid mesoporous carbon functionalized with sulfated zirconia (SZr-C). SZr-C has a surface area of approximately 1300 m2 g-1, and the total pore volume of 0.94 cm3g-1, composed mainly of mesoporous with an average pore size of 3.5 nm. The composition of the surface and the chemical states of the elements did reveal Zr isolated species. According to the data collected by infrared spectroscopy (FTIR), of pyridine desorbed at various temperatures, the total number of acidic sites was 2.36 mmol/g and the distribution in weak- medium, strong and super acidic sites was determined. The activity in the methylation of aniline indicated that the acid sites are strong, and have not redox properties.
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    Synthesis and characteristics of magnetite containing-cmk-3 and its application in hydrogen storage
    (2020) Juárez, Juliana M.; Venosta, Lisandro F.; Gómez Costa, Marcos B.; Anunziata, Oscar A.
    In this work, we report the synthesis and characterization of iron oxide nanoparticles (Magnetite) supported on CMK-3. The materials were characterized by XRD, SEM, TEM, XPS and magnetization studies. A large amount of the iron incorporated as iron oxide nanoparticles was in the magnetite phase. The incorporation of magnetite on the CMK-3 carbon surface significantly improved the hydrogen storage capacity (4.45 wt. % at 77 K and 10 bar) compared to the CMK-3 structure (2.20 wt% at 77 K and 10 bar). Magnetite nanoparticles play a key role in H2 adsorption.
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    Superacid mesoporous carbón base don sulfated Zr
    (2020) Anunziata, Oscar A.; Martínez, María Laura
    In 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.
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    Multiple-wall carbón nanotubes obtained with mesoporous material decorated with cerio-zirconium
    (2020) Martínez, María Laura; Anunziata, Oscar A.
    In this work, Ce-Zr-SBA-15 has been used directly as a catalyst for the synthesis of multi-vall carbon nanotubes (MWCNT) through Chemical Vapor Deposition (CVD). In addition to cerium oxide, it contains zirconium oxide Nano crystallites, which act as catalysts for carbon nanostructures. The catalytic performance of this material was evaluated for the decomposition of ethanol at 900 °C, with N2 flow. The structural characterization of the resulting catalyst was carried out by means of SEM and XRD. The decomposed carbon of absolute ethanol diffuses through the surface of the nanostructured material and precipitates in carbon structures called multiple-walled nanotubes, which could be visualized/detected/identified by TEM, showing diameters of the carbon nanotubes that range from 15 to 25 nm.
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    Direct synthesis and characterization of mesoporous carbon CMK-3 modified with zirconia applied in energy storage
    (2020) Venosta, Lisandro F.; Gómez Costa, Marcos B.; Juárez, Juliana M.; Anunziata, Oscar A.
    In this work, we report the synthesis and characterization of the nanostructured carbon material (CMK- 3) modified with zirconium oxide synthesized by a new direct synthesis technique. The aim of this new synthesis method is to avoid the use of inorganic siliceous template (SBA-15), which leads to a shorter and cheaper way to obtain mesoporous carbon, and at the same time incorporate into the framework Zirconium atoms. Zirconium oxide dispersed in carbon materials (Zr-CMK-3) were successfully synthesized and characterized by X-ray diffraction, textural properties, UV-Vis-DRS, XPS, and transmission electron microscopy analysis. This material is promising in the application of hydrogen adsorption for energy storage. Zr-CMK-3 material significantly improved H2 storage behavior (4.6% by weight at 77 K and 10 bar) compared to CMK-3 support. The synthesized material is promising in the absorption of hydrogen by weak bonding forces (physisorption). A hydrogen adsorption mechanism was proposed and the role of the Zr+4 cation in hydrogen absorption was discussed. The activity of the samples to the adsorption of hydrogen molecules is attributed to the improved dispersion of the zirconium oxide, as well as the appropriate use of support, which can probably disperse the zirconium on its large surface area, allowing a great dispersion of the zirconium. The Zr+4 cation is an active species to absorb and store hydrogen through a physisorption process and the carbon plays an important role in the dispersion and size of metal particles. A hydrogen storage mechanism on the active surface of the ZrO2 clusters was proposed. First layer of hydrogen molecules can react with the metal cation through a dihydrogen complex (Kubas interaction) [1]. The second layer of hydrogen molecules adsorbed around the metal oxide clusters is due to dipole-like interactions, this is because the metal particle induces dipole forces on the hydrogen molecule. The other layers could also interact by dipole forces; however, the interaction force decreases as the distance to the surface increases. The interaction of the induced dipole in a second layer adsorbs more hydrogen molecules because the strong interaction of the metal particles takes up dipole-induced forces on the hydrogen molecules. The upper layers could interact with the metal cation by dipole-induced bonding; however, the interaction force decreases as the distance to the surface increases. The procedure for this adsorption is still under investigation and optimization. The hydrogen storage behavior in Zr-CMK-3 can be optimized by controlling the size of the metal particles, the dispersion and the nature of the support.