Facultad Regional Córdoba

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    2,5-DMF production through hydrogenation of 5 HMF over noble metal catalysts supported on Ti modified SBA-15.
    (Univesidsad Tecnológica Nacional., 2017) Ledesma , Brenda Cecilia; Beltramone , Andrea Raquel
    Catalytic hydrogenolysis reaction of 5-hydroxymethylfurfural platform molecule to produce 2,5-dimethylfuran conversion was studied. For that purpose noble metal (Pt and Ir) catalysts supported on SBA-15 and Ti-SBA-15 supports were used. All of the tested catalysts were able to convert completely HMF. However, among the mentioned catalysts, the bimetallic Pt-Ir catalyst supported on Ti-SBA-15 showed the best behavior in terms of DMF selectivity, probably due to Ti incorporation and the synergic effect with the noble metals. Moreover, this catalyst was studied in order to know the influence of some reaction parameters on DMF selectivity. As results obtained, the increment of the pressure and the bimetallic formation improved the DMF selectivity. Keywords: Bimetallic, Hydrogenolysis, biomass, titanium
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    Probing the Catalytic Activity of Sulfate-Derived Pristine and Post-Teatred Porous TiO2(101) Anatase Mesocrystals by the Oxidative Desulfurization of Dibenzothiophenes.
    (Univesidsad Tecnológica Nacional., 2017) Rivoira , Lorena Paola; Martínez , María Laura; Falcón , Horacio; Beltramone , Andrea Raquel; Campos , Martín; Fierro, José; Tartaj, Pedro; Martínez , María Laura
    Mesocrystals (basically nanostructures showing alignment of nanocrystals well beyond crystal size) are attracting considerable attention for modeling and optimiza- (heterogeneous catalysis), only those mesocrystals with excellent textural properties are expected to fulfill their potential. This is especially true for oxidative desulfuration of dibenzothiophenes (hard to desulfurize organosulfur com pounds found in fossil fuels). Here, we probe the catalytic activity of anatases for the oxidative desulfuration of dibenzothiophenes under atmospheric pressure and mild temperatures. Specifically, for this study, we have taken advantage of the high stability of the (101) anatase surface to obtain (pores around 3−4 nm and surface areas around 200 m2 /g). Ultimately, this stability has allowed us to compare the catalytic activity of anatasesthat expose a high number of aligned single crystal-like surfaces while differing in controllable surface essential for oxidative desulfuration and that both elimination of sulfates and good textural properties significantly improve the catalytic activity. Furthermore, the most active mesocrystals have been used to model the catalytic reaction in three-(oil− the oil to the solvent phase partially limits the oxidative process and to estimate an apparent activation energy for the oxidative establish that (101) anatase mesocrystals with excellent textural propertiesshow adequate stability to withstand several post treatments without losing their initial mesocrystalline character and therefore could serve as modelsfor catalytic processes different from the one studied here.
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    Síntesis, Caracterización y Reactividad en ODS de mesocristales coloidales de TiO2.
    (Univesidsad Tecnológica Nacional., 2016) Rivoira , Lorena Paola; Martínez , María Laura; Falcón, Horacio; Beltramone , Andrea Raquel; Tartaj, Pedro; Campos , Martín; Fierro, José; Martínez , María Laura
    La desulfuración oxidativa (ODS) de combustibles líquidos representa una tecnología alternativa eficiente para complementar la HDS de dibenzotiofenos. Opera en condiciones moderadas de presión y temperatura. Se demuestra en este trabajo que los mesocristales con estructura anatasa, de tamaño coloidal monodisperso y excelentes propiedades texturales, pueden oxidar eficazmente al dibenzotiofeno (DBT) a sulfonas. La caracterización mediante UV/Vis-DRS de los catalizadores desarrollados indican la presencia mayoritaria de especies Ti (IV) con coordinación tetraédrica, pero se también se han detectado especies tetraédricas. Se obtuvo elevada actividad catalítica en la ODS de DBT, esta podría deberse a especies de Ti(IV) con coordinación tetraédrica disperso en un sustrato de elevada área superficial. Estos resultados corroboran la implicancia del mecanismo de crecimiento de los mesocristales, ya que sugieren que las especies terminales son similares a otras nanoestructuras no orientadas. Se muestra que un tratamiento que reduzca la cantidad de sulfatos residuales sobre la superficie da lugar a un incremento de la actividad catalítica de los mesocristales en esta reacción. Este hecho se atribuye a que la eliminación de los grupos sulfato residuales probablemente implica la formación de un número mayor de especies Ti (IV) con coordinación tetraédrica. Palabras clave: Desulfuración Oxidativa (ODS), dibenzotiofeno (DBT), mesocristales, anatasa, óxido de Titanio
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    Effect of geogrid reinforcement on interface for a stratified embankment
    (Geotech., 2016) Useche Infante, Danny José; Aiassa Martínez, Gonzalo Martín; Arrúa, Pedro Ariel; Eberhardt, Marcelo Gabriel
    Reinforced granular embankments are often placed on soft soil strata for an efficient and economical transfer of superstructure load. This paper describes laboratory tests on circular footing supported on unreinforced and geogrid-reinforced granular soil. Two types of geogrid layer, uniaxial and biaxial geogrid, were placed at the interface of sub-base soil and granular base of an embankment formed on soft ground to support shallow foundations. Load test were conducted with the aim to determine the performance improvement of the circular footing due to the provision of both types of geogrid reinforcement in the soil. Also studied the effect produced by anchoring geogrid layer at the edge of the mold sample. The results showed that the inclusion of a geogrid layer at the interface of sub-base soil and granular base increase the magnitude of the footing bearing capacity and decreases the settlement of the system. The study shows that the type of geogrid used has direct influence on stress-strain behavior of soil-geogrid system and better results occurred when the geogrid was anchored to test mold.
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    Calibración de modelo hidromecánico en mezclas de loess y bentonita
    (Tecnología y Ciencia - UTN, 2016) Alercia Biga, Carolina; Arrúa, Pedro Ariel; Aiassa Martínez, Gonzalo Martín; Eberhardt, Marcelo Gabriel
    Los suelos loessicos de la Ciudad de Córdoba, constituyen uno de los materiales más importantes empleados en obras de ingeniería especialmente en obras viales. Se han realizado importantes estudios investigando sus propiedades geotécnicas. En este trabajo, se realizaron ensayos de compresión no confinada y ensayos de infiltración mediante el empleo de un permeámetro a pared flexible. Se realizaron mezclas de suelo loessico con adición de bentonita en distintos porcentajes. Se evaluó el contenido de humedad, peso unitario seco y contenido de bentonita en las muestras remoldeadas. Se compararon los resultados obtenidos experimentalmente con los modelos propuestos mediante formulaciones matemáticas. Los resultados muestran que es posible lograr una aproximación entre el comportamiento hidromecánico teórico obtenido mediante la modelación y calibración de funciones racionales respecto del comportamiento empírico obtenido como resultado de ensayos en mezclas de suelo loessico estabilizadas con bentonita.
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    Prediction of infiltration on small scale field tests performance in compacted loessic soil
    (Geotech., 2015) Aiassa Martínez, Gonzalo Martín; Arrúa, Pedro Ariel; Eberhardt, Marcelo Gabriel
    Silty loess soils are widely spread on Córdoba city, Argentina. The ability to use this soil improved by compaction on embankments it is of interest to different types of local constructions, with purpose of reducing settlements and infiltration. This work research the water infiltration through compacted silty soils from Córdoba by small scale field test. Four small test embankments were constructed on natural soil with different compaction conditions using local silty soils. The site was characterized by typical geotechnical laboratory and field tests. The infiltration tests were performed using double ring infiltrometers for a time period around of 2 months. Results were used to field permeability estimated (kf) and these were compared with laboratory results (kl). Conclusions regarding the behavior observed in the field are presented.
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    Hydraulic conductivity in loessic stabiblized soil
    (Geotech, 2015) Alercia Biga, Carolina; Arrúa , Pedro A.; Eberhardt, Marcelo G.; Aiassa Martínez, Gonzalo Martín
    Loessic soils are the main geological storage available as a building material in Cordoba, Argentina. They are a typically kind of clayed silty soil with a metastable structure. Their structure makes them sensitive to collapse and sliding upon wetting. This has an important influence on mechanical and hydraulic behavior. Thus, usually their hydraulic properties are modified by compaction methods or by bentonite addition. Infiltration tests were done using remolded samples and a flexible wall permeameter. Compression tests were executed in a universal compression machine. Were performed in addition, capillary rise assays. Water content, dry unit weight, and percentages of ionic stabilizer and bentonite have been studied. Experiment results were compared between mixtures with different percentages of additives. The results show that the infiltration volume decreases with increasing content of bentonite in all remoulded samples tested respect to those natural soil remoulded samples, and it has been identified that the addition of bentonite increases the compressive strength by 400%.
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    Reservorio nanoscópico de hidrógeno a partie de biorresiduos de cáscara de naranjas.
    (Univesidsad Tecnológica Nacional., 2022) Juárez , Juliana María; Ledesma , Brenda Cecilia; Anunziata , Oscar Alfredo; Gómez Costa , Marcos Bruno; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Ledesma , Brenda Cecilia
    Este trabajo aborda el enfoque de valorización de biorresiduos para el desarrollo de un novedoso nanomaterial carbonoso para ser utilizado en la adsorción de hidrógeno como una alternativa en el uso de hidrógeno verde. En esta investigación, los carbones activados se sintetizaron a partir de cáscara de naranja utilizando diferentes condiciones de síntesis. Con los carbones activados obtenidos con la mejor estructura y textura se estudió la adsorción de hidrógeno y los efectos en la meso/microporosidad de estos. La activación del carbón se realizó mediante un proceso químico con ácido fosfórico como agente activador, variando la concentración de ácido, la relación sustrato / agente activador y el tiempo de contacto entre ellos. El mejor material se obtuvo utilizando tiempo de carbonización de 1 h, temperatura de carbonización de 470oC, concentración de ácido fosfórico de 50% en peso y con área BET de 1402 m2 / g. Dicho material mejoró significativamente el comportamiento de almacenamiento de H2 en comparación con el carbón nanoestructurado del tipo CMK-3 (3,1% en peso a -196,15 oC y 10 bar). El material sintetizado es prometedor en la absorción de hidrógeno por fuerzas de enlace débiles (fisisorción).
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    Sulfated/Zr-containing mesoporous carbons: a promising nanostructured catalytic material.
    (Univesidsad Tecnológica Nacional., 2021) Anunziata , Oscar Alfredo; Martínez , María Laura; Martínez , María Laura
    In this work, we report the successful preparation of a promising material with acidic properties from starch-derived mesoporous carbon (SMC), functionalized with sulfated zirconia (SZr-SMC). 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. SZr- SMC has a surface area of approximately 1300 m2/g, and a total pore volume of 0.94 cm3/g, 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 not reveal ZrO2 as isolated clusters. Ammonia thermodesorption studies indicated that, SZr-SMC retains 2.49 mmol/g of NH3 at very high temperature, exhibiting a strong acidity. 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 and isopropanol dehydration indicated that the acid sites are strong, and have not redox properties. A new and promising catalytic material based on mesoporous carbons modified with sulfated Zr is developed, which opens a wide range of acid-catalyzed reactions applied to industrial and medical processes.
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    HaP/SBA-3 Nanostructured Composite to Remove Fluoride Effectively from Contaminated Water.
    (Univesidsad Tecnológica Nacional., 2021) Cussa , jorgelina; López, Claudia; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; López, Claudia
    Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and textural properties, were successfully applied to remove fluoride from contaminated water. The proposed procedure to prepare HaP/SBA-3 was successful, which acts as supports to anchor the HaP crystals, in nanometer-scale (<2nm), with higher fluoride retention from contaminated water. The free OH- groups of HaP nanocrystals, within the host, facilitated the high-performance fluoride trapping. The fluoride retention activity was much higher than that of pure HaP and the composites HaP/SBA-15 and HaP/MCM-41. Keywords: F- retention; Contaminated water; HaP/SBA-3; Nanocomposites