Sonia Giraldo - Profile on Academia.edu (original) (raw)
Papers Vol. 9 núm. 17 enero-junio 2013 by Sonia Giraldo
"En este artículo se presenta el efecto de las sales inorgánicas MgSO4, NaCl y CaCO3 en la desinf... more "En este artículo se presenta el efecto de las sales inorgánicas MgSO4, NaCl y CaCO3 en la desinfección fotocatalítica del agua. Se usó TiO2-P25 como fotocatalizador y E. Coli como microorganismo contaminante. Las pruebas de desinfección se realizaron mediante la iluminación controlada de reactores batch cargados con agua contaminada, sales y TiO2. Los resultados de estas pruebas fueron usados para determinar los parámetros cinéticos de un modelo tipo Langmuir-Hinshelwood. Se encontró que las sales tienen una fuerte influencia sobre la inactivación fotocatalítica de E. Coli, y que cada sal y su concentración afectan la desinfección de forma diferente y en el siguiente orden: NaCl>CaCO3>>MgSO4. Adicionalmente, el valor de los parámetros calculados fue diferente para cada sal, evidenciando que las sales afectan el proceso por varios mecanismos relacionados con las interacciones ion-bacteria, ion-especie oxidante e ion-TiO2."
Papers by Sonia Giraldo
International Journal of Photoenergy, 2012
This paper reports the characterization and photoactivity of Ag-TiO 2 materials using different a... more This paper reports the characterization and photoactivity of Ag-TiO 2 materials using different amounts of silver during the hydrothermal synthesis. Photocatalysts were characterized by means of TEM, XPS, XRD, DRS, and N 2 sorption isotherms to determine the textural properties. The photocatalyst's configuration was observed to be as anatase-brookite mixed phase particles with Ag partially oxidized aggregates on the TiO 2 surface, which increased visible light absorption of the material. Moreover, photoproduction of singlet oxygen was followed by EPR analysis under visible light irradiations following the formation of TEMPOL. Such photoproduction was totally decreased by using the singlet oxygen scavenger DABCO. Photocatalysts were tested towards the photocatalytic disinfection of water suing a solar light simulator and an interior-light irradiation setup. Results evidenced an increase in the photooxidative effect of TiO 2 , while dark processes evidenced that part of the inactivation process is due to the Ag-TiO 2 surface bactericidal effect and possible lixiviated Ag + .
CT&F - Ciencia, Tecnología y Futuro, 2013
he kinetics parameters for the simultaneous reactions of hydrodesulfurization and hydrogenation o... more he kinetics parameters for the simultaneous reactions of hydrodesulfurization and hydrogenation of synthetic Fluid Catalytic Cracking (FCC) naphtha over CoMo/g-Al2O3 catalyst were determined. The proposed kinetic model considered a Langmuir-Hinshelwood adsorption mechanism (with 16 steps) with just one kind of active site. The amount of experimental data obtained was relatively limited, thus a genetic algorithm accompanied by an optimization through the Nelder-Mead Simplex method were used for the parameter estimations. Trimethylpentenes and 2-methylthiophene were used as representative molecules of unsaturated and sulfur compounds in FCC naphtha respectively. It was possible to calculate kinetic and thermochemical parameters, such as activation energies, adsorption heats and frequency factors with a good enough approach. This methodology results very useful since it allows the parameters determination with accuracy, reducing the amount of experimentation in comparison with traditional methodologies.
![Research paper thumbnail of Corrigendum to Improving the selectivity in hydrocracking of phenanthrene over mesoporous Al-SBA-15 based Fe-W catalysts by enhancing mesoporosity and acidity [ Applied Catalysis A: General 510 (2016) 98–109]](https://attachments.academia-assets.com/122343849/thumbnails/1.jpg)
](Applied Catalysis A: General, 2017
Improving the selectivity in hydrocracking of phenanthrene over mesoporous Al-SBA-15 based Fe–W catalysts by enhancing mesoporosity and acidity
Applied Catalysis A: General, 2016
Abstract Catalysts for heavy oil hydrocracking require an enhanced mesoporosity (higher pore diam... more Abstract Catalysts for heavy oil hydrocracking require an enhanced mesoporosity (higher pore diameters) and a moderate acidic function (mild acidity) to treat the bulky molecules present in this kind of feedstock and to yield middle distillates (MD). In this work, we have synthesized five different kinds of mesoporous silica based on SBA-15 by modifying some of the variables of their synthesis with the aim at enhancing mesoporosity. NH4F and 1,3,5-trimethylbenzene (TMB) were used to modify the mesostructured arrangement in SBA-15. TMB modified SBA-15 materials exhibited the highest textural properties (2.16 cm3 g−1 and 17 nm) in comparison to NH4F modified silica (1.90 cm3 g−1 and 10.8 nm) and pristine SBA-15 silica (1.03 cm3 g−1 and 12 nm). The acidity of the SBA-15 based materials was modified by a post-synthesis “grafting procedure” to Si/Al molar ratios of 10, 25, and 40. SBA-15 based materials modified with both Al and TMB were used as supports for Fe–W sulfides. These catalysts were tested in the hydrocracking of phenanthrene. In general, all of the catalysts supported on Al-SBA-15 based materials were selective to the ring opening reaction of phenanthrene in contrast to the results obtained over a commercial Ni–Mo/ɤ-Al2O3 catalyst. Such trend was associated to the presence of Bronsted acid sites on the surface of the Al modified supports as shown 27Al MAS NMR analysis.
Use of the 2-propanol decomposition as a technique for the characterization of the acid-base properties of hydrotreating CoMo catalysts
The acid-base properties of CoMo catalysts supported on amorphous alumino-silicates (ASA) with di... more The acid-base properties of CoMo catalysts supported on amorphous alumino-silicates (ASA) with different Si/(Si+Al) atomic ratios and on alumina modified with B were determined using the 2-propanol decomposition reaction. Results were compared and validated with isopropylamine decomposition tests and with FT-IR measurements of adsorbed pyridine. A good reproducibility and high sensitivity of the 2-propanol dehydration reaction to changes and/or modifications of the catalyst surface were observed. In the case of the CoMo catalysts supported on ASA, density, strength and total active sites number increases when the Si/(Si+Al) ratio increases. This fact is attributed to an increase in the Brönsted acid sites. On the other hand, an increase in density and strength of acid sites with the increase in the B amount was observed in the case of CoMo catalysts modified with B. The results of this study support the conclusion that the selectivity in the decomposition of 2-propanol reaction is s...
EFFECT OF THE PRESENCE OF CHLORINE IN Pd/γ-Al2O3 CATALYSTS ON THE DIBENZOTIOPHENE HYDRODESULFURIZATION REACTION
In this work, the influence of chlorine in Pd/γ-Al2O3 catalysts was studied, in order to understa... more In this work, the influence of chlorine in Pd/γ-Al2O3 catalysts was studied, in order to understand the reason of the improvement in the conversion observed in the hydrodesulfurization (HDS) of dibenzotiophene (DBT), when these catalysts are prepared from chlorided precursors compared to those prepared from acetylacetonates. In order to achieve this objective, the effect of the incorporation of Cl before and after the Pd salt, and the effect of changing catalysts calcinations and reduction temperatures was analyzed. The acid-base properties of the catalyst were determined using the Proton Affinity Distribution method, which allowed correlating the nature and concentration of the different OH sites present in the catalyst's surface with the catalytic behavior. The results showed that the presence of Cl in the catalyst generates changes in the acid properties of the support, possibly creating new acid Brönsted sites, presenting a positive effect in the HDS of the DBT. It was also ...
Performance of noble metal-Mo/γ-Al2O3 catalysts: Effect of preparation parameters
Studies in Surface Science and Catalysis, 1999
The catalytic performance of bimetallic catalysts NM-Mo (NM=Pt, Pd, Ru) supported on γ-alumina wa... more The catalytic performance of bimetallic catalysts NM-Mo (NM=Pt, Pd, Ru) supported on γ-alumina was evaluated in simultaneous hydrodresulfurization (HDS) and hydrogenation (HYD) reactions. Nature of noble metal, calcination temperature after noble metal impregnation, activating mixture composition and the effect of the impregnation of noble metal on MoS2/γ-Al2O3 were the parameters studied. Results show that the noble metal nature and impregnation
Applied Catalysis A: General, 2014
USY zeolite catalysts were chemically modified by treatment with aqueous solutions of sodium ethy... more USY zeolite catalysts were chemically modified by treatment with aqueous solutions of sodium ethylenediaminetetraacetic acid (EDTA) to study the effect of removal of extraframework aluminum species (EFAl) on hydrocracking performance. The textural, structural and acidic properties were characterized by XRD, elemental analysis, XPS, N 2 physisorption, HRTEM, 29 Si and 27 Al solid-state NMR, ammonia TPD and IR spectroscopy of adsorbed pyridine. The acid catalytic activity of the zeolites was measured by the conversion of propane and 1,3,5-tri-isopropylbenzene. EDTA is a selective agent for the extraction of EFAl from USY preserving the framework Al content. Concomitant with EFAl removal, EDTA enhances the textural properties and changes bulk and surface properties, in particular the Al speciation. Hydrocracking catalysts were prepared from the modified USY zeolites and alumina loaded with a P-promoted NiMo-sulfide phase. Their performance was evaluated in the hydrocracking of a heavy vacuum gas oil under conditions close to the industrial practice. The most active hydrocracking catalyst is obtained by removal of a relatively small amount of EFAl from the USY zeolite. The mild EDTA treatment to achieve this selectively extracts amorphous EFAl species from the mesopore system, resulting in better access to acid sites and an increase of the concentration of strong Brønsted acid sites. Severe EDTA treatment resulted in lower hydrocracking activity which was ascribed to progressive leaching of EFAl synergistically involved in the cracking catalysis. The present study therefore points out the importance of the presence of some EFAl species for the hydrocracking of real feedstocks. This work also shows that even with supports with increased mesoporosity and stronger acid character, higher hydrocracking activity of a real feedstock is not guaranteed.
Applied Catalysis A: General, 2014
Materials Chemistry and Physics, 2011
The photocatalytic oxidation of the azo dye Orange-II (Or-II) using Fe loaded TiO 2 (Fe-TiO 2 ) w... more The photocatalytic oxidation of the azo dye Orange-II (Or-II) using Fe loaded TiO 2 (Fe-TiO 2 ) was studied under ultraviolet (UV), visible (vis) and simultaneous UV-vis irradiations using a solar light simulator. Photocatalysts were characterized by means of XRD, SEM-EDX, FTIR and DRS. Fe 3+ species, identified in XPS analyses, were responsible of the increased absorption of visible light. Moreover, DRS analyses showed a decrease in the bandgap due to Fe 3+ loading. Photocatalystic tests proved that Fe modification enhanced the TiO 2 photocatalytic activity towards Or-II photodegradation under simultaneous UV-vis irradiation. Even so, the performance of the Fe-TiO 2 samples towards the photodegradation of phenol, under UV irradiation, was lower than TiO 2 suggesting the recombination of the UV photogenerated electron-hole pair. Therefore, results evidence a Fe 3+ promotion of the electron caption in the photosensitization process of TiO 2 by Or-II acting as a sensitizer. Such process leads to the Or-II photooxidation under UV-vis irradiation by losing energy in electron transferring processes to sensitize TiO 2 , and, the formation of reactive oxygen species promoted by the injected electron to the TiO 2 conduction band.
Reactivity of dibenzothiophene type molecules over Pd catalysts
Journal of Molecular Catalysis A: Chemical, 2009
The reactivity of dibenzothiophene (DBT) over Pd/γ-Al2O3 catalysts and the possible nature of the... more The reactivity of dibenzothiophene (DBT) over Pd/γ-Al2O3 catalysts and the possible nature of the Pd active phase were analyzed. DBT conversion was studied as a function of the activating agent, the temperature, and in the presence of naphthalene (NP). Pd showed a high selectivity to the hydrogenation (HYD) route of DBT hydrodesulfurization (HDS). However, activation with H2S decreased HYD selectivity.
Fe-modified TiO2 photocatalysts for the oxidative degradation of recalcitrant water contaminants
Catalysis Today, 2010
Fe–TiO2 with enhanced photocatalytic oxidation activity was synthesized by hydrolysis of titanium... more Fe–TiO2 with enhanced photocatalytic oxidation activity was synthesized by hydrolysis of titanium butoxide. Sol–gel process leads to less active Fe–TiO2 particles than bare TiO2; meanwhile, the hydrothermal synthesis of Fe–TiO2 seems to promote the stabilization of Fe3+ in the TiO2 structure promoting the photo-oxidation activity of TiO2 towards the degradation of azo-dyes and the inactivation of Escherichia coli (E. coli)
"En este artículo se presenta el efecto de las sales inorgánicas MgSO4, NaCl y CaCO3 en la desinf... more "En este artículo se presenta el efecto de las sales inorgánicas MgSO4, NaCl y CaCO3 en la desinfección fotocatalítica del agua. Se usó TiO2-P25 como fotocatalizador y E. Coli como microorganismo contaminante. Las pruebas de desinfección se realizaron mediante la iluminación controlada de reactores batch cargados con agua contaminada, sales y TiO2. Los resultados de estas pruebas fueron usados para determinar los parámetros cinéticos de un modelo tipo Langmuir-Hinshelwood. Se encontró que las sales tienen una fuerte influencia sobre la inactivación fotocatalítica de E. Coli, y que cada sal y su concentración afectan la desinfección de forma diferente y en el siguiente orden: NaCl>CaCO3>>MgSO4. Adicionalmente, el valor de los parámetros calculados fue diferente para cada sal, evidenciando que las sales afectan el proceso por varios mecanismos relacionados con las interacciones ion-bacteria, ion-especie oxidante e ion-TiO2."
International Journal of Photoenergy, 2012
This paper reports the characterization and photoactivity of Ag-TiO 2 materials using different a... more This paper reports the characterization and photoactivity of Ag-TiO 2 materials using different amounts of silver during the hydrothermal synthesis. Photocatalysts were characterized by means of TEM, XPS, XRD, DRS, and N 2 sorption isotherms to determine the textural properties. The photocatalyst's configuration was observed to be as anatase-brookite mixed phase particles with Ag partially oxidized aggregates on the TiO 2 surface, which increased visible light absorption of the material. Moreover, photoproduction of singlet oxygen was followed by EPR analysis under visible light irradiations following the formation of TEMPOL. Such photoproduction was totally decreased by using the singlet oxygen scavenger DABCO. Photocatalysts were tested towards the photocatalytic disinfection of water suing a solar light simulator and an interior-light irradiation setup. Results evidenced an increase in the photooxidative effect of TiO 2 , while dark processes evidenced that part of the inactivation process is due to the Ag-TiO 2 surface bactericidal effect and possible lixiviated Ag + .
CT&F - Ciencia, Tecnología y Futuro, 2013
he kinetics parameters for the simultaneous reactions of hydrodesulfurization and hydrogenation o... more he kinetics parameters for the simultaneous reactions of hydrodesulfurization and hydrogenation of synthetic Fluid Catalytic Cracking (FCC) naphtha over CoMo/g-Al2O3 catalyst were determined. The proposed kinetic model considered a Langmuir-Hinshelwood adsorption mechanism (with 16 steps) with just one kind of active site. The amount of experimental data obtained was relatively limited, thus a genetic algorithm accompanied by an optimization through the Nelder-Mead Simplex method were used for the parameter estimations. Trimethylpentenes and 2-methylthiophene were used as representative molecules of unsaturated and sulfur compounds in FCC naphtha respectively. It was possible to calculate kinetic and thermochemical parameters, such as activation energies, adsorption heats and frequency factors with a good enough approach. This methodology results very useful since it allows the parameters determination with accuracy, reducing the amount of experimentation in comparison with traditional methodologies.
Applied Catalysis A: General, 2017
Improving the selectivity in hydrocracking of phenanthrene over mesoporous Al-SBA-15 based Fe–W catalysts by enhancing mesoporosity and acidity
Applied Catalysis A: General, 2016
Abstract Catalysts for heavy oil hydrocracking require an enhanced mesoporosity (higher pore diam... more Abstract Catalysts for heavy oil hydrocracking require an enhanced mesoporosity (higher pore diameters) and a moderate acidic function (mild acidity) to treat the bulky molecules present in this kind of feedstock and to yield middle distillates (MD). In this work, we have synthesized five different kinds of mesoporous silica based on SBA-15 by modifying some of the variables of their synthesis with the aim at enhancing mesoporosity. NH4F and 1,3,5-trimethylbenzene (TMB) were used to modify the mesostructured arrangement in SBA-15. TMB modified SBA-15 materials exhibited the highest textural properties (2.16 cm3 g−1 and 17 nm) in comparison to NH4F modified silica (1.90 cm3 g−1 and 10.8 nm) and pristine SBA-15 silica (1.03 cm3 g−1 and 12 nm). The acidity of the SBA-15 based materials was modified by a post-synthesis “grafting procedure” to Si/Al molar ratios of 10, 25, and 40. SBA-15 based materials modified with both Al and TMB were used as supports for Fe–W sulfides. These catalysts were tested in the hydrocracking of phenanthrene. In general, all of the catalysts supported on Al-SBA-15 based materials were selective to the ring opening reaction of phenanthrene in contrast to the results obtained over a commercial Ni–Mo/ɤ-Al2O3 catalyst. Such trend was associated to the presence of Bronsted acid sites on the surface of the Al modified supports as shown 27Al MAS NMR analysis.
Use of the 2-propanol decomposition as a technique for the characterization of the acid-base properties of hydrotreating CoMo catalysts
The acid-base properties of CoMo catalysts supported on amorphous alumino-silicates (ASA) with di... more The acid-base properties of CoMo catalysts supported on amorphous alumino-silicates (ASA) with different Si/(Si+Al) atomic ratios and on alumina modified with B were determined using the 2-propanol decomposition reaction. Results were compared and validated with isopropylamine decomposition tests and with FT-IR measurements of adsorbed pyridine. A good reproducibility and high sensitivity of the 2-propanol dehydration reaction to changes and/or modifications of the catalyst surface were observed. In the case of the CoMo catalysts supported on ASA, density, strength and total active sites number increases when the Si/(Si+Al) ratio increases. This fact is attributed to an increase in the Brönsted acid sites. On the other hand, an increase in density and strength of acid sites with the increase in the B amount was observed in the case of CoMo catalysts modified with B. The results of this study support the conclusion that the selectivity in the decomposition of 2-propanol reaction is s...
EFFECT OF THE PRESENCE OF CHLORINE IN Pd/γ-Al2O3 CATALYSTS ON THE DIBENZOTIOPHENE HYDRODESULFURIZATION REACTION
In this work, the influence of chlorine in Pd/γ-Al2O3 catalysts was studied, in order to understa... more In this work, the influence of chlorine in Pd/γ-Al2O3 catalysts was studied, in order to understand the reason of the improvement in the conversion observed in the hydrodesulfurization (HDS) of dibenzotiophene (DBT), when these catalysts are prepared from chlorided precursors compared to those prepared from acetylacetonates. In order to achieve this objective, the effect of the incorporation of Cl before and after the Pd salt, and the effect of changing catalysts calcinations and reduction temperatures was analyzed. The acid-base properties of the catalyst were determined using the Proton Affinity Distribution method, which allowed correlating the nature and concentration of the different OH sites present in the catalyst's surface with the catalytic behavior. The results showed that the presence of Cl in the catalyst generates changes in the acid properties of the support, possibly creating new acid Brönsted sites, presenting a positive effect in the HDS of the DBT. It was also ...
Performance of noble metal-Mo/γ-Al2O3 catalysts: Effect of preparation parameters
Studies in Surface Science and Catalysis, 1999
The catalytic performance of bimetallic catalysts NM-Mo (NM=Pt, Pd, Ru) supported on γ-alumina wa... more The catalytic performance of bimetallic catalysts NM-Mo (NM=Pt, Pd, Ru) supported on γ-alumina was evaluated in simultaneous hydrodresulfurization (HDS) and hydrogenation (HYD) reactions. Nature of noble metal, calcination temperature after noble metal impregnation, activating mixture composition and the effect of the impregnation of noble metal on MoS2/γ-Al2O3 were the parameters studied. Results show that the noble metal nature and impregnation
Applied Catalysis A: General, 2014
USY zeolite catalysts were chemically modified by treatment with aqueous solutions of sodium ethy... more USY zeolite catalysts were chemically modified by treatment with aqueous solutions of sodium ethylenediaminetetraacetic acid (EDTA) to study the effect of removal of extraframework aluminum species (EFAl) on hydrocracking performance. The textural, structural and acidic properties were characterized by XRD, elemental analysis, XPS, N 2 physisorption, HRTEM, 29 Si and 27 Al solid-state NMR, ammonia TPD and IR spectroscopy of adsorbed pyridine. The acid catalytic activity of the zeolites was measured by the conversion of propane and 1,3,5-tri-isopropylbenzene. EDTA is a selective agent for the extraction of EFAl from USY preserving the framework Al content. Concomitant with EFAl removal, EDTA enhances the textural properties and changes bulk and surface properties, in particular the Al speciation. Hydrocracking catalysts were prepared from the modified USY zeolites and alumina loaded with a P-promoted NiMo-sulfide phase. Their performance was evaluated in the hydrocracking of a heavy vacuum gas oil under conditions close to the industrial practice. The most active hydrocracking catalyst is obtained by removal of a relatively small amount of EFAl from the USY zeolite. The mild EDTA treatment to achieve this selectively extracts amorphous EFAl species from the mesopore system, resulting in better access to acid sites and an increase of the concentration of strong Brønsted acid sites. Severe EDTA treatment resulted in lower hydrocracking activity which was ascribed to progressive leaching of EFAl synergistically involved in the cracking catalysis. The present study therefore points out the importance of the presence of some EFAl species for the hydrocracking of real feedstocks. This work also shows that even with supports with increased mesoporosity and stronger acid character, higher hydrocracking activity of a real feedstock is not guaranteed.
Applied Catalysis A: General, 2014
Materials Chemistry and Physics, 2011
The photocatalytic oxidation of the azo dye Orange-II (Or-II) using Fe loaded TiO 2 (Fe-TiO 2 ) w... more The photocatalytic oxidation of the azo dye Orange-II (Or-II) using Fe loaded TiO 2 (Fe-TiO 2 ) was studied under ultraviolet (UV), visible (vis) and simultaneous UV-vis irradiations using a solar light simulator. Photocatalysts were characterized by means of XRD, SEM-EDX, FTIR and DRS. Fe 3+ species, identified in XPS analyses, were responsible of the increased absorption of visible light. Moreover, DRS analyses showed a decrease in the bandgap due to Fe 3+ loading. Photocatalystic tests proved that Fe modification enhanced the TiO 2 photocatalytic activity towards Or-II photodegradation under simultaneous UV-vis irradiation. Even so, the performance of the Fe-TiO 2 samples towards the photodegradation of phenol, under UV irradiation, was lower than TiO 2 suggesting the recombination of the UV photogenerated electron-hole pair. Therefore, results evidence a Fe 3+ promotion of the electron caption in the photosensitization process of TiO 2 by Or-II acting as a sensitizer. Such process leads to the Or-II photooxidation under UV-vis irradiation by losing energy in electron transferring processes to sensitize TiO 2 , and, the formation of reactive oxygen species promoted by the injected electron to the TiO 2 conduction band.
Reactivity of dibenzothiophene type molecules over Pd catalysts
Journal of Molecular Catalysis A: Chemical, 2009
The reactivity of dibenzothiophene (DBT) over Pd/γ-Al2O3 catalysts and the possible nature of the... more The reactivity of dibenzothiophene (DBT) over Pd/γ-Al2O3 catalysts and the possible nature of the Pd active phase were analyzed. DBT conversion was studied as a function of the activating agent, the temperature, and in the presence of naphthalene (NP). Pd showed a high selectivity to the hydrogenation (HYD) route of DBT hydrodesulfurization (HDS). However, activation with H2S decreased HYD selectivity.
Fe-modified TiO2 photocatalysts for the oxidative degradation of recalcitrant water contaminants
Catalysis Today, 2010
Fe–TiO2 with enhanced photocatalytic oxidation activity was synthesized by hydrolysis of titanium... more Fe–TiO2 with enhanced photocatalytic oxidation activity was synthesized by hydrolysis of titanium butoxide. Sol–gel process leads to less active Fe–TiO2 particles than bare TiO2; meanwhile, the hydrothermal synthesis of Fe–TiO2 seems to promote the stabilization of Fe3+ in the TiO2 structure promoting the photo-oxidation activity of TiO2 towards the degradation of azo-dyes and the inactivation of Escherichia coli (E. coli)
Applied Catalysis A: General, 2012
CoMo catalysts supported on sodium-doped amorphous aluminosilicates (ASA) with different Si/(Si +... more CoMo catalysts supported on sodium-doped amorphous aluminosilicates (ASA) with different Si/(Si + Al) ratios were prepared. The catalytic performance of these catalysts in the HDT of synthetic FCC naphtha was compared with the one of a CoMo catalyst supported on pure alumina, as well as with another one supported on sodium-modified alumina. The catalysts results were also compared with the ones of CoMo catalyst supported on ASA without sodium. The catalysts were characterized by XRF, XRD, Raman, as well as their textural and acid properties. The sodium introduction simultaneously with the variation of the Si/(Si + Al) ratio conducts to obtain a catalyst (15% Si/(Si + Al), 3 wt.% Na) with, on the one hand, an Mo oxide species distribution with an important participation of -CoMoO 4 crystalline species and, on the other hand, a selective formation of weak Brönsted acid sites. As a consequence of this especial balance between the acid properties and the oxidic Mo-surface-species distribution, this catalyst presented an activity similar to the one of the CoMo/Al 2 O 3 , but with improvements in the selectivity to HDS. Additionally, it was also encountered that when CoMo catalysts supported on materials of predominantly acidic nature are used, the linear olefins inhibit more the HDS activity than the branched ones, whereas the contrary effect was encountered when supports of a predominantly basic nature are used.