Browsing by Author "Martínez , María Laura"

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    Controlled Release of Haloperidol from a novel SWCNT Nano composite coated with ZnO nanocrystals.
    (Univesidsad Tecnológica Nacional., 2023) Anunziata , Oscar Alfredo; Cussa , jorgelina; Martínez , María Laura; Martínez , María Laura; Cussa , jorgelina
    Starting from the physicochemical knowledge of the host properties of the na noscale systems would be applied to drug dosage [1,2]. We propose NM synthesis strategies that offer the necessary characteristics for these processes. First, we study the physicochemistry of the anchoring sites of the respective hosts (chemical bonds with reversible or irreversible adsorption) or physisorption (straightforward interactions). Then, whether to design carbon based nanomaterials (CNM), or nano engineered materials, containing the respective active sites (deposited or generated nanospecies), capable of interacting with the aforementioned hosts such as: redox sites, proton acceptor sites, electron donor-acceptor sites, to allow HOMO-LUMO chemical interactions that satisfy the needs of the process to be studied. The nanostructures that allow free diffusions and reversible adsorptions, dosage of molecules with applications in nanokinetics, etc., and determination of critical molecular sizes, calculated using experimental methods, and methods such as density functional theory and semiempirical methods, to avoid steric hindrances between molecules and 100 80 40 60 8 12 16 20 Experimental data Weibull Ritger-Peppas Higuchi Drug Released , % mol/w Time (h) 4 20 nanomaterials whether 2D or 3D, designing NMs with large surface area, physical, ther mal and chemical stability, and pore size, and adequate pore size. Advancing in this sense, this work studies the usage of: Haloperidol Release from ZnO nanocrystal Coated SWCNT, with 30nm of wide and 5 um of long, which by the effect of the interaction between the host and drug molecules and by diffusion through the porosity, leads to a substantial contribution to controlled drug release. The reduction in the dose and frequency of administration, possible improvement in the selectivity of the pharmacological activity, and a prolonged therapeutic effect. CNT prepared by sol gel method (using the same technique describe by us, [3]), but at different pH and long range of pristine mesoporous carbons material calcination, to obtain SWCNTs. The posterior deposition of ZnO, was obtained, employing ZnNO3, activated under N2 flow at 500ºC; offering adequate LUMO of Zn (the hybridized MO) for Haloperidol interactions. Haloperidol competitively blocks postsynaptic dopamine (D2) receptors in the meso limbic system of the brain, thereby eliminat ing dopamine neurotransmission and leading to antidelusionary and antihallucinagenic effects. Specifically, the dose of Haloperidol (potent antipsychotic drug), indicates that its release follows the so called "power law" or Weibull model, based on the results we obtained in our laboratory
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    Eliminación de azufre mediante desulfuración oxidativa con Ti-SBA-16. Parte I. Síntesis y caracterización.
    (Univesidsad Tecnológica Nacional., 2015) Rivoira , Lorena Paola; Vallés , Verónica Alejandra; Ledesma , Brenda Cecilia; Ponte , María Virginia; Martínez , María Laura; Beltramone , Andrea Raquel; Martínez , María Laura; Ponte , María Virginia; Ledesma , Brenda Cecilia; Ledesma , Lorena Paola; Vallés , Verónica Alejandra
    Se desarrollaron catalizadores tipo SBA-16 modificados con Ti como TiO2 y como heteroatomo y se probaron en la desulfuración oxidativa (ODS) del dibenzotiofeno predominante en el combustible líquido. Se utilizó TiO2 puro como referencia para comparar la actividad catalitica. Los catalizadores fueron caracterizados mediante análisis químico, XRD, EDX y TEM. El estado de coordinación tetraédrico del titanio (en la muestra de Ti-SBA-16) u octaédrico (en la muestra de TiO2/SBA-16) en la matriz de sílice se determinó por XPS, UV-vis DRS, FTIR, Raman y XANES. La actividad catalítica se muestra en la Parte 2 de este trabajo.
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    Experimental Desing Optimization of the ODS of DBT using V2O5 supported on Ga-SBA-15.
    (Univesidsad Tecnológica Nacional., 2020) Rivoira , Lorena Paola; Cussa , jorgelina; Martínez , María Laura; Beltramone , Andrea Raquel; Martínez , María Laura; 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 v1/15 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.
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    Experimental desing optimization of the ods of DBT using V2O5 supported on GA-SBA-15.
    (Univesidsad Tecnológica Nacional., 2020) Rivoira , Lorena Paola; Cussa , jorgelina; Martínez , María Laura; Beltramone , Andrea Raquel; Martínez , María Laura; 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 substrate/catalyst mass 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 4 wt.% of gallium and 6 wt.% of vanadium; the optimal ratio between g DBT/g of catalyst was 4 and the molar ratio H2O2/DBT was 5. The incorporation of gallium as heteroatom in tetrahedral position allows the better anchorage of the active species of vanadium generating a very well dispersed catalyst. 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. The experiment design was able to find the best combination between the heteroatom and the vanadium active site in order to find the most active catalyst for ODS of DBT at the optimized experimental conditions.
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    Experimental desing optimization of the ODS of DBT using V2O5 supported on GA-SBA-15.
    (Univesidsad Tecnológica Nacional., 2020) Rivoira , Lorena Paola; Cussa , jorgelina; Martínez , María Laura; Beltramone, Andrea Raquel
    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 substrate/catalyst mass 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 4 wt.% of gallium and 6 wt.% of vanadium; the optimal ratio between g DBT/g of catalyst was 4 and the molar ratio H2O2/DBT was 5. The incorporation of gallium as heteroatom in tetrahedral position allows the better anchorage of the active species of vanadium generating a very well dispersed catalyst. 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. The experiment design was able to find the best combination between the heteroatom and the vanadium active site in order to find the most active catalyst for ODS of DBT at the optimized experimental conditions.
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    Hydrodeoxygenation of guayacol over platinum modified mesoporous catalysts.
    (Univesidsad Tecnológica Nacional., 2018) Rivoira , Lorena Paola; Martínez , María Laura; Beltramone , Andrea Raquel; Martínez , María Laura
    Biomass pyrolysis results in fuel bio-oil which can be consider as a renewable petroleum alternative. Bio-oil obtained by this process presents high oxygen content, becoming into a corrosive and unstable fuel. Hydrodeoxygenation (HDO) is a catalytic treatment that improves the bio-oil characteristics. There are more than 400 organic compounds that can be found in bio oil. For that reason we selected guayacol (2-methoxyphenol ó 4-hydroxy-3-methoxybenzyl) as model compound to test the catalytic activity of the developed catalysts. The catalysts tested for hydrodeoxygenation (HDO) of guayacol to produce deoxygenated products such as benzene, toluene, ciclohexene and ciclohexane were platinum modified mesoporous SBA-15 and Ga-SBA 15. The synthetized catalysts were obtained by sol-gel method. Active platinum sites were incorporated by wet impregnation. The system reaction used for HDO is a 600 mL stirred autoclave (Parr Pressure Reactor 4536). Reaction conditions were carried out at 230°C and 12 atm of H2 under 500 rpm. Reactor feed consisted in 50 mL of a 1% w/v solution of guayacol in dodecane. Then, 200 mg of the catalyst was transferred to the reactor. Samples were taken every hour. Products were analysed with HP Series II GC and HP-5 capillary column and identified by GC/MS. Better catalytic results were obtained when Ga was introduced as heteroatom into the SBA-15 siliceous framework. Textural and structural properties of the Pt -supported mesoporous catalysts were determined along with the nature of the active site. The synthetized material were characterized before and after the incorporation of metal active site by XRD, HRTEM, SEM EDX, FTIR, XPS and N2 adsorption-desorption isotherms. Characterization results demonstrated that highly dispersed Pt species are responsible for the high activity in the guayacol conversion. The most active catalyst for HDO of guayacol was Pt/Ga-SBA-15 achieving 99 % of guayacol conversion in a relatively short time (4 h). Gallium atoms incorporated into the support modified the nature of the SBA-15 surface by conferring Bronsted and Lewis acidity. The acid sites are able to interact with the platinum active sites improving the activity of the catalyst. As consequence the gallium modified catalyst showed better dispersion of the Pt sites
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    ODS of dibenzothiopene with titanium-modified SBA-16.
    (Univesidsad Tecnológica Nacional., 2015) Rivoira , Lorena Paola; Vallés , Verónica Alejandra; Ledesma , Brenda Cecilia; Martínez , María Laura; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Martínez , María Laura
    Over the past, oxidative desulfurization (ODS) has drawn considerable interest as a new alter native method for deep sulfur elimination from light oils. This can be attributed to its attrac tive properties, including lower temperature and pressure conditions and lower operating cost [1-3] than conventional hydrodesulfurization (HDS) process. Oxidation of organosulfur com pounds results in the formation of sulfoxides/sulfones, highly polar and hence easily removed by both extraction into polar solvents or by adsorption. Due to their low reactivity, diben zothiophene derivatives (DBTs) are the most refractory species to be eliminated from oils. Hence, the ODS process through which DBTs are converted to their corresponding sulfones involves great interest at present [4-6]. We recently reported a good performance of this sup port in hydrotreating processes [7]. In this work, we describe the preparation and characteriza tion of new mesoporous catalytic materials based on Ti-containing SBA-16. We study here, the effect of the preparation method of titania-modified SBA-16 (characteristics of the active Ti and/or TiO2 species) and the effect of the different operation conditions in ODS of DBT under mild conditions in order to find the best performance. TiO2-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. 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 tempe rature, nature of the substrate and reuse of catalysts)
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    ODS of dibenzothiophene over V-SBA-15 mesoporous material.
    (Univesidsad Tecnológica Nacional., 2016) Rivoira , Lorena Paola; Martínez , María Laura; Falcón, Horacio; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Martínez , María Laura
    Oxidative desulfurization (ODS) is considered a new alternative method for deep sulfur elimination from light oils. This can be due to its attractive properties, including lower temperature and pressure conditions and lower operating cost than conventional hydrodesulfurization process. Oxidation of organosulfur compounds results in the formation of sulfoxides/sulfones, highly polar and hence easily removed by both extraction into polar solvents or by adsorption. The oxidation of DBTs with organic hydroperoxides or H2O2 was studied over various catalytic heterogeneous systems, such as supported oxide metals or titanium silicalites1-9. Vanadosilicates were used as catalysts for the desulfurization of light oil10-12. The oxidation of (DBTs) was also performed using WOx/ZrO2 catalyst13, supported Pd, Cr2O3, unsupported manganese oxides and a commercial Co Mo/Al2O3 with hydrogen peroxide as oxidant14. In general, when tetravalent cations like Ti4+, Zr4+, V4+, Sn4+, etc. are incorporated to the framework of SBA 15, the electroneutrality is maintained but some redox properties are incorporated to the support surface15,16 . In this work we evaluate vanadium modified mesoporous SBA-15 in the ODS of dibenzothiophene as a model sulfur compound
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    Optimización de la síntesis del material mesoestructurado SBA-3 mediante diseño experimental.
    (Univesidsad Tecnológica Nacional., 2016) Ponte, María Virginia; Rivoira , Lorena Paola; Cussa , Jorgelina; Martínez , María Laura; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Martínez , María Laura; Cussa , jorgelina; Rivoira , Lorena Paola
    El material SBA-3 está constituido por una estructura de sílice mesoporosa de ordenamiento de poros regular hexagonal, diámetro de poro >3nm; presenta alta área superficial y alto volumen de poro. Se utilizó la metodología de Superficie de Respuesta para el modelado y optimización de las condiciones de síntesis de SBA-3. Se analizaron como factores del Diseño la influencia de la relación molar entre el surfactante (CTAB) y la fuente de silicio (TEOS), el tiempo de envejecimiento, la temperatura y el pH de la síntesis utilizando HCl. La respuesta analizada fue la intensidad de difracción de rayos X para el plano [100]. Las superficies de respuestas se obtuvieron con el diseño Box–Behnken, buscando la combinación de los parámetros que dieran como resultado la mejor estructura en el material sintetizado. Mediante la aplicación de metodología estadística, los mayores valores de la función objetivo (intensidad de DRX para el plano [100]) se obtuvieron utilizando valores de la relación molar CTAB/TEOS de 0,07-0,16; HCl/TEOS de 8-11; temperatura de síntesis de 35-45 (ºC) y tiempos de envejecimiento de 12-24hr.
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    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 Paola
    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).
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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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    Sílica Gel como fuente de silicio: Síntesis y caracterización de matrial mesoporoso.
    (Univesidsad Tecnológica Nacional., 2015) Ponte , María Virginia; Martínez , María Laura; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Martínez , María Laura
    El material mesoporoso SBA-3 fue sintetizado mediante el método sol-gel, utilizando silicato de sodio como fuente de silicio y bromuro de hexadeciltrimetilamonio (CTAB) como agente director de estructura en condiciones acidas. El silicato sódico se generó in-situ por disolución de silica gel en NaOH. Se estudió el efecto de la variación de temperatura, la concentración de NaOH, y el tiempo de reacción. El mejor material mesoporoso con estructura SBA-3 fue obtenido con las siguientes condiciones de síntesis: temperatura: 25ºC; tiempo de reacción: 45min; concentración de NaOH: 0.8M.
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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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    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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    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 Alejandra
    TiO2-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.
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    Sulfur elimination by oxidative desulfurization with titanium-modified SBA-16L.
    (Univesidsad Tecnológica Nacional., 2016) Rivoira , Lorena Paola; Vallés , Verónica Alejandra; Ledesma , Brenda Cecilia; Martínez , María Laura; Anunziata , Oscar Alfredo; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Martínez , María Laura; Ledesma , Brenda Cecilia; Vallés , Verónica Alejandra
    Over the past, oxidative desulfurization (ODS) has drawn considerable interest as a new alter native method for deep sulfur elimination from light oils. This can be attributed to its attrac tive properties, including lower temperature and pressure conditions and lower operating cost [1-3] than conventional hydrodesulfurization (HDS) process. Oxidation of organosulfur com pounds results in the formation of sulfoxides/sulfones, highly polar and hence easily removed by both extraction into polar solvents or by adsorption. Due to their low reactivity, diben zothiophene derivatives (DBTs) are the most refractory species to be eliminated from oils. Hence, the ODS process through which DBTs are converted to their corresponding sulfones involves great interest at present [4-6]. We recently reported a good performance of this sup port in hydrotreating processes [7]. In this work, we describe the preparation and characteriza tion of new mesoporous catalytic materials based on Ti-containing SBA-16. We study here, the effect of the preparation method of titania-modified SBA-16 (characteristics of the active Ti and/or TiO2 species) and the effect of the different operation conditions in ODS of DBT under mild conditions in order to find the best performance. TiO2-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. 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 tempe rature, nature of the substrate and reuse of catalysts).
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    Superacid Mesoporous Carbons Based on Sulfated Zr.
    (Univesidsad Tecnológica Nacional., 2020) Anunziata , Oscar Alfredo; Martínez , María Laura; 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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    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 Alfredo
    Highly 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)
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    Synthesis of SBA-1, SBA-3 and SBA-7 mesoporous materials. Study of the effect of time and temperature.
    (Univesidsad Tecnológica Nacional., 2018) Martínez , María Laura; Ponte , María Virginia; Falcón, Horacio; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Ponte , María Virginia
    In recent years, physicists, chemists and engineers have focused their research on the design of new functional materials. In the synthesis and control of materials in nanometer dimensions, the aim is currently directed towards the development of systems and devices that take advantage of chemical properties and physical principles, where their causes lie in the nanometer scale. Although there are numerous investigations about the synthesis of mesoporous materials from inorganic silicon salt, for example the synthesis of SBA-3. Ting et al [1] studied the synthesis of SBA-1; they obtained mesoporous SBA-1 with cubic structures, with a high porous system, by utilizing agents’ routers short chain structure such as the dodecyltrimethyl ammonium chloride. Recent research also showed that the formation of mesophases is affected by the presence of the counter ions and templates or surfactants can adopt a mesophase or other phases. So, Che et al. [2] found a phase shift 2D-hexagonal cubes from P6mm to Pm3n. We have published results for synthesis of SBA-3 with silica gel as silica source; we have found that the formation of mesophase is function of NaOH concentration in the dissolutions of silica gel. The influence of reaction temperature, time and NaOH concentration was investigated. During studies for the best synthesis conditions for synthesis of SBA-3, we also obtained SBA-1 and SBA-7 mesoporous materials.
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    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., 2017) Rivoira , Lorena Paola; Martínez , María Laura; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Anunziata , Oscar Alfredo
    Vanadium pentoxide 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 with Al and Ga as heteroatom substituting Si. 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 depends on the vanadium loading and on the nature of the support. The more acidic support allowed better dispersion of the vanadium species. 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 (H2O2) as oxidant and acetonitrile as solvent. 100% of DBT elimination was attained at a