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Author: search.filters.author.Vallés , Verónica AlejandraSubject: search.filters.subject.ODS

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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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    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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    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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    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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    Sulfur elimination by ODSwith 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; Ledesma, Brenda; Vallés , Verónica Alejandra
    Nanostructured carbon CMK-3 and mesoporous silica SBA-15 modified with Fe by using different sources of Fe, were used in the oxidative desulfurization (ODS) of dibenzothiophene (DBT) as a model sulfur compound. Fe-CMK-3 and Fe-SBA-15 were prepared by wetness impregnation using FeCl3.6H2O and FeNO3.9H2O as different sources of Fe. A solution of FeCl3.6H2O/ FeNO3.9H2O in ethanol was mixed with the corresponding material solution (CMK-3 or SBA-15) at room temperature. The solution was placed in a rotary evaporator to remove excess of ethanol at about 333 K and 60 rpm. Afterwards, the sample was dried at 373 K for 18 h and was thermally treated in a dynamic inert (N2) atmosphere. The percentage of Fe has been 2 wt.% with respect to carbon in the final FeCl3-CMK-3 and FeNO3-CMK-3 material. Four samples modified with Fe have been prepared and were characterized by XRD, FTIR, XPS, BET, TEM and SEM. These studies indicated that it was possible to obtain a CMK-3 replica successfully from SBA-15, using sucrose as a carbon precursor. Wide angle XRD pattern of the sample modified with FeCl3.6H2O implies the formation of the magnetite phase in the silica channels. The nanomaterial area is significantly smaller with the incorporation of the metal, SBA-15 and CMK-3`s characteristic structure is maintained after the metal is within the host, in agreement with the XRD studies. The catalytic activity was improved when the nanoporous materials were modified with Fe. The nanoporous carbon modified with FeCl3.6H2O 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 short time in mild conditions.