Browsing by Author "Korili, Sophia A."

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    PublicationOpen Access
    Adsorption of rhodamine 6G and humic acids on composite bentonite-alginate in single and binary systems
    (Springer, 2018) Gomri, Fatima; Finqueneisel, Gisele; Zimny, Thierry; Korili, Sophia A.; Gil Bravo, Antonio; Boutahala, Mokhtar; Institute for Advanced Materials and Mathematics - INAMAT2
    In this work, the preparation, characterization, and sorption of rhodamine 6G and humic acids on a composite sodium alginate-bentonite were investigated. Their structure and morphology were analyzed by several techniques, including Fourier transform infrared spectroscopy, X-ray diffraction, and N-2 adsorption at - 196 degrees C. A synergetic sorption mechanism was observed in binary systems; humic acids adsorption was enhanced by the presence of Rh6G in the mixture. The kinetic studies revealed that the sorption follows a pseudo-first-order kinetic model and the sorption capacities of Rh6G increased with the pH value. The Langmuir isothermal model well described the adsorption isotherm data, showing a maximum adsorption capacity for Rh6G up to 429.5 mg/g at 20 degrees C. On the basis of the data of the present investigation, it is possible to conclude that the composite exhibited excellent affinity for the dye and humic acids, and it can be applied to treat wastewater containing dye and natural organic matter.
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    PublicationOpen Access
    Adsorption recovery of Ag(I) and Au(III) from an electronics industry wastewater on a clay mineral composite
    (University of Science and Technology Beijing, 2019) Rakhila, Youness; Elmchaouri, Abdellah; Mestari, Allal; Korili, Sophia A.; Abouri, Meriem; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias
    The aim of this work is to investigate the ability of an adsorbent of a clay mineral composite to remove and recover gold and silver ions from wastewater. The composite was prepared by mixing phosphogypsum (PG), obtained from an industrial waste, and a natural clay mineral. The materials were characterized before and after use in adsorption by several techniques. Batch adsorption experiments were carried out, and the effects of the contact time and the pH and temperature of solution on the removal processes were investigated. The optimum pH for the adsorption was found to be 4. The adsorption of these metal ions reached equilibrium after 2 h of contact. The pseudo-first- and the pseudo-second-order kinetic models, as well as the Freundlich and the Langmuir isotherm equations, were considered to describe the adsorption results. The maximum adsorbed amount of 85 mg·g−1 Ag(I) and 108.3 mg·g−1 Au(III) was found. The recovery of the adsorbed gold and silver ions from the adsorbent was also analyzed. Strong acids appeared to be the best desorption agents to recover gold and silver ions. The use of aqua regia gave regeneration rates close to 95.3% and 94.3% for Ag(I) and Au(III), respectively. Finally, the removal of gold and silver ions from an industrial wastewater was tested in batch experiments, and percentage recoveries of 76.5% and 79.9% for Ag(I) and Au(III), respectively, were obtained. To carry out the industrial application of the proposed methodology, an economic viability study is required.
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    PublicationOpen Access
    Analysis by temperature-programmed reduction of the catalytic system Ni-Mo-Pd/Al2O3
    (Elsevier, 2023) Pedroarena Apezteguía, Iván; Grande López, Lucía; Torrez Herrera, Jonathan Josué; Korili, Sophia A.; Gil Bravo, Antonio; Institute for Advanced Materials and Mathematics - INAMAT2; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    Alumina-supported nickel catalysts are used to facilitate many reactions at various scales. However, the deactivation of these catalysts is an important problem that has prompted the search for solutions such as the addition of other metals that act as promoters. In this research, the interactions that form between the support and the metals have been studied, a fundamental property that directly affects the performance of the catalyst. With this idea, several Ni-Pd and Ni-Mo bimetallic and various Ni-Mo-Pd trimetallic samples have been prepared, and the reduction capacity of the oxide phases by temperatura-programmed reduction has been analyzed and studied. It has been found that in bimetallic catalysts, Pd favors the appearance of NiO species that are more easily reducible than Mo. In the same way, the data obtained from the trimetallic simples suggest that the impregnation order of Mo and Pd is not a determining factor in these catalysts. In addition, it has been found that the co-impregnation of Ni with Pd gives better results than the sequential impregnation of these metals. The results obtained have also shown that the order of nickel impregnation is decisive. In the case of Ni-Mo catalysts, by impregnating the molybdenum first, catalysts with better reducing properties can be obtained.
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    PublicationOpen Access
    Application of industrial wastes from chemically treated aluminum saline slags as adsorbents
    (American Chemical Society, 2018) Gil Bravo, Antonio; Arrieta Chango, Ekhine; Vicente, Miguel Ángel; Korili, Sophia A.; Institute for Advanced Materials and Mathematics - INAMAT2
    In this study, industrial wastes, which remain after aluminum extraction from saline slags, were used as adsorbents. The aluminum saline slags were treated under reflux with 2 mol/dm3 aqueous solutions of NaOH, H2SO4, and HCl for 2 h. After separation by filtration, aqueous solutions containing the extracted aluminum and residual wastes were obtained. The wastes were characterized by nitrogen adsorption at -196 °C, X-ray diffraction, scanning electron microscopy, and ammonia pulse chemisorption. The chemical treatment reduced the specific surface area, from 84 to 23 m2/g, and the pore volume, from 0.136 to 0.052 cm3/g, of the saline slag and increased the ammonia-adsorption capacity from 2.84 to 5.22 cm3/g, in the case of acid-treated solids. The materials were applied for the removal of Acid Orange 7 and Acid Blue 80 from aqueous solutions, considering both single and binary systems. The results showed interesting differences in the adsorption capacity between the samples. The saline slag treated with HCl rapidly adsorbed all of the dyes present in solution, whereas the other materials retained between 50 and 70% of the molecules present in solution. The amount of Acid Orange 7 removed by the nontreated material and by the material treated with NaOH increased in the presence of Acid Blue 80, which can be considered as a synergistic behavior. The CO2 adsorption of the solids at several temperatures up to 200 °C was also evaluated under dry conditions. The aluminum saline slag presented an adsorption capacity higher than the rest of treated samples, a behavior that can be explained by the specific sites of adsorption and the textural properties of the solids. The isosteric heats of CO2 adsorption, determined from the Clausius-Clapeyron equation, varied between 1.7 and 26.8 kJ/mol. The wastes should be used as adsorbents for the selective removal of organic contaminants in wastewater treatment.
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    PublicationOpen Access
    Bimetallic (Pt-Ni) La-hexaaluminate catalysts obtained from aluminum saline slags for the dry reforming of methane
    (Elsevier, 2021) Torrez Herrera, Jonathan Josué; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    This work describes the synthesis of platinum-nickel/lanthanum hexaaluminates (PtNi/LHA) and their performance in terms of stability and catalytic activity in the dry reforming of methane (DRM) at 973 K. An Al solution (9.40 g/L) obtained from an Al saline slag waste by acid extraction was used to synthesize the hexaaluminate by mixing with a stoichiometric amount of lanthanum nitrate and methanol/Peg400/PegMn400 under hydrothermal conditions at 493 K for 16 h. After calcination at 1473 K for 2 h, the presence of LHA was confirmed. Wet impregnation of the synthesized support was used to obtain an initial Ni/LHA catalyst (10 wt% NiO) and the modified PtNi/LHA catalysts (0.2–1 wt% Pt). The support and catalysts were characterized by X-ray diffraction (XRD), N2 adsorption at 77 K, temperature- programmed reduction (TPR), scanning electron microscopy (SEM) and transmission electron microscopy (HR- TEM). The analysis of the TPR patterns for the catalysts allowed the type of metal support interaction and NiO species to be determined, with a weak interaction with the support being observed in all cases. The presence of Pt promoted NiO reducibility. The PtNi/LHA catalysts synthesized were found to be active and very stable in the DRM reaction after reaction for 50 h. The catalytic behavior was evaluated from the CO2 and CH4 conversions, as well as the H2/CO selectivity, with values of between 89% and 92% in almost all the time range evaluated. The presence of Pt improved the stability and catalytic performance of Ni/LHA thus improving resistance to coke formation.
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    Catalytic photodegradation of organic compounds using TiO2/pillared clays synthesized using a nonconventional aluminum source
    (Elsevier, 2022-10-15) Cardona Rodríguez, Yaneth; Wegrzyn, Agnieszka; Miskowiec, Pawel; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    This study evaluates the photocatalytic degradation of 2,6-dichlorophenol (2,6-DCP), triclosan (TCS) and bisphenol A (BPA) by ultraviolet (UV) and visible (VIS) light in the presence of TiO2/catalysts synthesized by wet impregnation followed by calcination. The catalyst supports used were three alumina pillared clays (Al-PILC) synthesized using various aluminum sources and montmorillonite (Mt) as raw material. One of the Al-PILC was prepared following the conventional method (Al-PILCCM), using a commercial aluminum salt, and the other two were synthesized using a saline slag, with the aluminum used being extracted with the alkaline (Al-PILCBE) or the acid (Al-PILCAE) method. Mt was impregnated with various amounts of titanium (1, 5, 10, and 20 wt% Ti) and evaluated for the photodegradation of the aforementioned pollutants, comparing the results with those obtained using commercial anatase. Due to the higher conversion rates, 10 and 20 wt% Ti were chosen to impregnate the Al-PILC and to evaluate the photocatalytic performance. All materials were characterized by several techniques, which confirmed the successful formation of TiO2 in the anatase phase. In all cases, photodegradation was higher when using UV light and the most photodegraded pollutant was TCS (85.15 ± 0.49%), followed by 2,6-DCP (65.43 ± 0.79%) and, to a lesser degree, BPA (36.15 ± 0.65%). Al-PILC showed higher photodegradation percentages, with Al-PILCAE exhibiting the highest values for both types of light. An analysis of the photoproducts by HPLC-MS suggested that the preferred pathway for TCS and 2,6-DCP photodegradation depends on the type of light used.
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    PublicationOpen Access
    Catalytic valorization of CO2 by hydrogenation: current status and future trends
    (Taylor and Francis, 2021) Sancho Sanz, Iris; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias
    Terrestrial environmental and biological systems are being threatened by the tremendous amount of human carbon dioxide emissions. Therefore, it is crucial to develop a sustainable energy system based on CO2 as chemical feedstock. In this review, an introduction to the CO2 activation and transformation has been made, together with a more comprehensive study of the catalytical reduction of CO2 to methane, methanol, and formic acid, which are currently contemplated as chemical feedstocks and/or promising energy carriers and alternative fuels.
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    PublicationOpen Access
    Comparative removal of emerging contaminants from aqueous solution by adsorption on an activated carbon
    (Taylor & Francis, 2019) Gil Bravo, Antonio; Taoufik, Nawal; García Mora, Ana María; Korili, Sophia A.; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias
    Batch sorption experiments were performed to study the adsorption of six emerging pollutants from aqueous solutions using a commercial granular activated carbon as adsorbent. Caffeine, clofibric acid, diclofenac, gallic acid, ibuprofen and salicylic acid were selected as representative contaminants. The activated carbon was characterized by nitrogen adsorption at 77 K, and through the determination of point of zero charge. The effects of several operational parameters, such as pH, initial concentration of organic molecules, mass of adsorbent and contact time, on the sorption behaviour were evaluated. The contact time to attain equilibrium for maximum adsorption was found to be 40 min. The kinetic data were correlated to several adsorption models, and the adsorption mechanism found to follow pseudo-second-order and intraparticle-diffusion models with external mass transfer predominating in the first 15 min of the experiment. The equilibrium adsorption data were analysed using the Freundlich, Langmuir and Toth isotherm equation models. The similar chemical structure and molecular weight of the organic pollutants studied to make the adsorption capacity of the activated carbon used very similar for all the molecules.
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    PublicationOpen Access
    A comparative study of the catalytic performance of nickel supported on a hibonite-type La-hexaaluminate synthesized from aluminum saline slags in the dry reforming of methane
    (Elsevier, 2022) Torrez Herrera, Jonathan Josué; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    In this work, a hibonite-type Ni/La-hexaaluminate (Ni/LHA) synthesized from an industrial waste is used and compared as catalyst in the dry reforming of methane (DRM) at 973 K. The structure, catalytic behavior, and stability during a run time of at least 50 h of three Nicatalysts obtained from two commercial supports and two preparation methods were used for comparison. An aluminum solution (9.40 g/L) obtained from an aluminum saline slag waste by acid extraction was used to synthesize the hexaaluminate by mixing with a stoichiometric amount of lanthanum nitrate and methanol/Peg400/PegMn400 under hydrothermal conditions at 493 K for 16 h. The Ni/LHA catalyst (10 wt% NiO) was obtained by impregnation of the synthesized support, calcined previously at 1473 K for 2 h. The resulting solids were characterized by several techniques as: X-ray diffraction (XRD), N2 adsorption at 77 K, temperature-programmed reduction (TPR), scanning electron microscopy (SEM) and transmission electron microscopy (HR-TEM). In order to compare the catalytic behavior and properties of the Ni/LHA catalyst, three Ni catalysts obtained from two commercial supports (g-Al2O3 and SiO2) and two preparation methods (wet impregnation (I) and precipitation-deposition (PD)) were synthesized. Analysis of the TPR patterns for the catalysts allowed the type of metal support interaction and NiO species to be determined, with a weak interaction with the support being observed in Ni/LHA and NieI/ SiO2. The NiO species observed, with crystallite sizes between 9.7 and 40.4 nm, confirm the X-ray structural analyses. The Ni/LHA catalyst was found to be active and very stable in the DRM reaction after 50 h. The catalytic behavior was evaluated from the CO2 and CH4 conversions, as well as the H2/CO selectivity, with values of 99% over almost all the time range evaluated. The behavior of this catalyst is comparable to that of NieI/Al2O3 and NiPD/SiO2. The results found indicating that the strong interaction of nickel with the support favors the stability of the catalysts in the DRM reaction.
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    PublicationOpen Access
    Development of ceramic-MOF filters from aluminum saline slags for capturing CO2
    (Elsevier, 2023) Torrez Herrera, Jonathan Josué; Korili, Sophia A.; Gil Bravo, Antonio; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    This study describes the procedures followed to synthesize ceramic-MOF filters using aluminum saline slag wastes. Briefly, the raw aluminum saline slags were washed at 80 ◦C to significantly reduce the saline content and eliminate gases. The pretreated material was mixed with glucose (G/S ratios between 0.2 and 1.6) and acetone by stirring for 4 h. After this time, the resulting solid was dried at 60 ◦C and then at 190 ◦C. During the glucose caramelization step, PegMn400 was also added and the temperature increased to 1200 ◦C. The obtained solid was impregnated with precursor solutions to achieve a supported ZIF-8 MOF. The ceramic-MOF filters were characterized by X-ray diffraction (XRD), N2 adsorption at 77 K, X-ray fluorescence (XRF), scanning electron microscopy (SEM) and transmission electron microscopy (HR-TEM), thereby confirming the presence of a structure that allows dispersion of the synthesized and supported ZIF-8. Finally, the performance of these ceramic-MOF filters as CO2 adsorbents was evaluated in the temperature range 50–300 ◦C, with isosteric heats of 19 kJ/mol being obtained using the Clausius-Clapeyron equation.
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    Development of Ni/Lahexaaluminates from aluminum saline slags applied as catalysts in the dry reforming of methane
    (2021) Torrez Herrera, Jonathan Josué; Gil Bravo, Antonio; Korili, Sophia A.; Química Aplicada; Kimika Aplikatua
    The general objective of this work is to study the synthesis methods, structural and morphological behavior of hexaaluminates and their performance as catalysts in the dry reforming reaction of methane from aluminum salt slags. Specific objectives: 1. Valorize the saline slag of aluminum and mitigate its polluting effect. 2. Obtaining an optimal method for the synthesis of hexaaluminates from salt slags. 3. Evaluation of the performance and applicability of catalysts in the dry reforming reaction. 4. Determination of the optimal operating parameters of the catalysts. 5. Determination of efficiency and comparison with catalysts synthesized with commercial precursors.
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    PublicationOpen Access
    Effect of gold nanoparticles on SiO2@g-C3N4 catalyst for the degradation of amoxicillin
    (Elsevier, 2024-11-12) Santamaría Arana, Leticia; Korili, Sophia A.; Gil Bravo, Antonio; López de Luzuriaga Fernández, José Manuel; Monge Oroz, Miguel; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    Gold nanoparticles in different proportions (0.5 and 1 %) have been grafted at the surface of a SiO2@g-C3N4 nanotube-based composite (SiO2 nanotubes obtained from halloysite clay) and also g-C3N4 (for comparison purposes) to test their degradation capacity over the antibiotic amoxicillin proving that the introduction of these nanoparticles on the catalyst modifies the degradation mechanism followed by the pollutant. Results obtained show that the introduction of the appropriate percentage of gold NPs in the composite improves amoxicillin degradation efficiency and establish a direct correlation between the presence of gold NPs and the production of ∙O2.
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    PublicationOpen Access
    Effect of high pressure on the reducibility and dispersion of the active phase of Fischer-Tropsch catalysts
    (MDPI, 2019) Yunes, Simón; Vicente, Miguel Ángel; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias
    The effect of high pressure on the reducibility and dispersion of oxides of Co and Fe supported on -Al2O3, SiO2, and TiO2 has been studied. The catalysts, having a nominal metal content of 10 wt.%, were prepared by incipient wetness impregnation of previously calcined supports. After drying at 60 °C for 6 h and calcination at 500 °C for 4 h, the catalysts were reduced by hydrogen at two pressures, 1 and 25 bar. The metal reduction was studied by temperature-programmed reduction up to 750 °C at the two pressures, and the metal dispersion was measured by CO chemisorption at 25 °C, obtaining values between 1% and 8%. The physicochemical characterization of these materials was completed by means of chemical analysis, X-ray diffraction, N2 adsorption-desorption at -196 °C and scanning electron microscopy. The high pressure lowered the reduction temperature of the metal oxides, improving their reducibility and dispersion. The metal reducibility increased from 42%, in the case of Fe/Al2O3 (1 bar), to 100%, in the case of Fe/TiO2 (25 bar).
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    Effect of the preparation method and metal content on the synthesis of metal modified titanium oxide used for the removal of salicylic acid under UV light
    (Taylor & Francis, 2018) Santamaría Arana, Leticia; Vicente, Miguel Ángel; Korili, Sophia A.; Gil Bravo, Antonio; Institute for Advanced Materials and Mathematics - INAMAT2
    Titanium dioxide modified with Ag and Fe was synthesized using two preparation methods, characterized and applied to the photocatalytic degradation of salicylic acid in aqueous solution. The modified TiO2 samples were prepared by the sol–gel and wet impregnation methods starting from titanium(IV) isopropoxide and using AgNO3 and Fe(NO3)3·9H2O as precursors of the modifiers, with their content varying between 0 and 5 wt.%. Catalysts characterization was based on powder X-ray diffraction (PXRD), nitrogen physisorption at 77 K, temperature programmed reduction (H2-TPR), chemisorption of NH3 at 343 K and X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation of salicylic acid by modified TiO2 was investigated under ultraviolet irradiation at 298 K considering various concentrations of the catalyst, between 100 and 1000 mgcatalyst/dm3, and of the organic molecule, between 0 and 15 mg/dm3. The catalysts most active in the degradation of salicylic acid were those having the highest Fe content. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
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    PublicationOpen Access
    Effect of the surface properties of Me2+/Al layered double hydroxides synthesized from aluminum saline slag wastes on the adsorption removal of drugs
    (Elsevier, 2020) Santamaría Arana, Leticia; Devred, F.; Gaigneaux, E. M.; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa; Gobierno de Navarra / Nafarroako Gobernua, PI017-PI039 CORRAL
    This work presents the synthesis of Me2+ (Co, Mg, Ni and Zn)/Al layered double hydroxides (LDH) with a 3:1 M ratio by the co-precipitation method. Structural characterization and comparison of the series has been achieved using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), nitrogen physisorption at 77 K, thermogravimetry measurements (TGA), temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), ammonia temperature-programmed desorption (NH3-TPD) and point of zero charge (pHpzc). Batch experiments were performed to analyze the adsorption capacity of the different LDH on diclofenac and salicylic acid, as example of emergent pollutants. The pH, mass of adsorbent, contact time and concentration of pollutant were the parameters used to compare the adsorption performance of the synthesized materials. Samples showed different behavior and the equilibrium was reached at different times, Mg6Al2 and Zn6Al2 showed lower equilibrium times but had higher adsorption capacity. Various adsorption and isotherm equation models were employed to study both the kinetic and equilibrium results and, in general, the removal of diclofenac was greater than that of salicylic acid. 1-Butanol conversion was also used as a means of acidity and basicity characterization and the results were compared with the adsorption performance of the samples in order to explain the results found. A relationship between the amount of pollutants adsorbed and the butenes formed in the dehydrogenation reaction of 1-butanol was found.
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    Effect of the synthesis method on the morphology, textural properties and catalytic performance of La-hexaaluminates in the dry reforming of methane
    (Elsevier, 2021) Torrez Herrera, Jonathan Josué; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    This work describes the synthesis of nickel/lanthanum hexaaluminates (NiO/LHA), optimizing the LHA synthesis method, as well as their performance in terms of stability and catalytic activity in the dry reforming of methane (DRM). The synthesis methods studied include co-precipitation, nitrate decomposition and freeze drying, using a La/Al molar ratio of 1:11 in all methods. Drying methods, namely oven drying (4 h at 353 K), vacuum drying (8 h at 353 K) + oven drying (2 h at 423 K) and heat treatment (12 h at 473 K) + oven drying (2 h at 373 K), were also optimized during selection of the final catalyst support. After calcination at 1473 K for 2 h, the presence of lanthanum aluminate (LaAlO3) and traces of LHA were found in all cases. Specific surface areas of 50, 32 and 30 m(2)/g were obtained for the samples AD1 (nitrate decomposition), FD1 (freeze drying), CP1 (co-precipitation). The nitrate decomposition method was selected and optimized to obtain the LHA structure at low temperature in the presence of Ni(II), using a La/Al/Ni molar ratio of 1/15/0.2. The results showed the formation of pure-phase hexaaluminate at 1473 K. The solids obtained were used as supports for nickel catalysts (10 wt%) for DRM at 973 K. The supports and catalysts were characterized by X-ray diffraction (XRD), N-2 adsorption at 77 K, temperature-programmed reduction (TPR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The simulation of the TPR patterns of the catalysts allowed determining the type of metal support interaction and the activation energy of the system as well as the rest of the kinetic parameters. A cumulative mean activation energy of 100.7 kJ/mol was determined for the catalysts. The metallic morphologies, dispersion and distribution of NiO on the surface of the LHA support were analyzed considering a theoretical simulation of the reduction profiles, obtaining an average growth factor of 1.4, which indicates that the metallic phase is growing in one and two dimensions. The NiO/LHA catalysts synthesized were found to be active and very stable in the DRM reaction after 20 h of reaction with an average selectivity H-2/CO upper than 0.90. The differences observed can be related to the textural properties developed during the optimized nitrate decomposition method. The characterization analysis by simulation, TPR, XRD, TEM, SEM allowed us to establish the effect of the textural properties, the metal interaction, the growth of the nickel grains and their distribution in the support on the catalytic performance in DRM. The better performance was obtained with the catalysts with higher porosity and greater support metal interaction, which allowed obtaining a better distribution of the metallic phase, thus generating less harmful carbonaceous species for the activity of the catalyst and therefore showing the best values of catalytic stability and conversion. Finally, three types of coke were identified from HR-TEM and EDS analysis: graphitic, filamentous and CNT, showing different effects on the catalytic behavior deactivation being the presence of graphitic more aggressive than the other two species.
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    Efficient recovery of aluminum from saline slag wastes
    (Elsevier, 2019) Yoldi Sangüesa, María; Fuentes Ordóñez, Edwin Gustavo; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Gobierno de Navarra / Nafarroako Gobernua, PI017 CORRAL
    This work presents the procedure to improve the aluminum extracted from a hazardous waste from the recycling of aluminum, aluminum that could be used in the production of value-added materials, as well as with the generation of non-hazardous waste. The aluminum waste was treated under reflux and stirring with NaOH aqueous solutions taking into account two concentrations (1 and 2 mol/dm3), various times of extraction (1, 2 and 4 h) and 4th consecutive steps of extraction in order to obtain solutions with Al3+. The activation of the waste by milling is also analyzed. After extraction, the solution is filtered to separate an aqueous solution that contain the extracted Al3+ and a residual waste. A maximum of 7.54 g/dm3 of aluminum was extracted in the first step, for a total accumulated of 9.59 g/dm3 of aluminum. The extracted aluminum can be used to synthesize added-value products applied as adsorbents and catalysts. Finally, the residual waste generated was characterized by N2 adsorption at −196 °C, X-ray diffraction, X-ray fluorescence, energy-dispersive X-ray and scanning electron microscopy in order to apply it as in future works adsorbent or catalyst.
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    Eliminación y valorización de CO₂ presente en efluentes gaseosos mediante adsorción y reformado seco de metano
    (2016) Garcés Polo, Siby Inés; Gil Bravo, Antonio; Korili, Sophia A.; Química Aplicada; Kimika Aplikatua
    El objetivo general de esta tesis doctoral ha sido la realización de un estudio en adsorción de CO₂ y su utilización en la reacción de reformado de metano como investigación base en las estrategias de eliminación y valorización de CO₂ de efluentes gaseosos. El plan de trabajo desarrollado se enmarcó en dos amplias áreas de interés actual como son la captura y la valorización de CO₂. Las actividades realizadas para alcanzar el objetivo trazado se englobaron en cada uno de los capítulos de esta memoria: 1. Estudio comparativo de la capacidad y cinética de adsorción de CO₂ de materiales microporosos (Capítulo III y IV). 2. Preparación y caracterización de óxidos mixtos de Co, Fe y Ni derivados de hidrotalcita (Capítulo VI). 3. Adsorción de CO₂ en óxidos mixtos derivados de hidrotalcita a altas presiones y temperaturas (Capítulo V).
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    Enhancing adsorptive performance of Cu-Al layered double hydroxides from aluminum saline slags: Insights from response surface methodology and molecular dynamic simulation
    (Elsevier, 2024-12-01) Boulahbal, Aziza Imene; Santamaría Arana, Leticia; Bourzami, Riahd; Bendrihem, Aymene Salah; Boutahala, Mokhtar; Korili, Sophia A.; Gil Bravo, Antonio; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2
    This study aims to optimize the adsorption process of gallic acid (GA) on Cu-Al layered double hydroxides (LDHs) synthesized via a co-precipitation method at various pH levels. The procedure is based on the adsorption of organic pollutants from aqueous solutions, with evaluations carried out based on operational parameters such as pH, initial concentration, and adsorbent quantity. Two series of LDHs were compared: one using aluminum extracted from saline slags and the other using a commercial aluminum salt as source of aluminum. Saline slags, a by-product of aluminum recycling, are particularly hazardous due to their high toxicity and potential for environmental contamination. Extracting aluminum from these slags and using it in the synthesis of LDHs not only helps in eliminating a dangerous waste but also creates materials with beneficial environmental applications. The adsorption process was optimized using response surface methodology (RSM) coupled with Box- Behnken design (BBD) to assess the effects of key operational parameters. Besides gallic acid, other organic pollutants such as diclofenac and salicylic acid were also evaluated for removal from aqueous solution. The LDH /LDO were characterized by X-ray diffraction (XRD), ATR infrared spectroscopy (ATR-IR), scanning and transmission electron microscopy (SEM/TEM), thermogravimetric analysis (TGA), and nitrogen adsorption at -196ºC. The merit data indicate that the material synthesized at pH = 9 with extracted aluminum exhibits superior adsorption capacity for gallic acid, demonstrating the highest removal rate, nearly reaching 100 %, and achieving equilibrium more quickly than other samples. This superior adsorption performance is also notable for salicylic acid and diclofenac. After four regeneration cycles, the adsorption rate of the adsorbent remains stable, indicating that CCA9 maintains a consistent and efficient adsorption performance. This highlights the robustness of the material and its high reusability in prolonged adsorption applications. Molecular dynamics simulations (MDS) revealed that the adsorption process occurs spontaneously, driven by weak interactions: van der Waals, intermolecular, hydrogen bonding, π-interactions and short contacts.
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    Estudio de la degradación de contaminantes emergentes mediante fotocatálisis heterogénea
    (2015) García Mora, Ana María; Gil Bravo, Antonio; Korili, Sophia A.; Escuela Técnica Superior de Ingenieros Agrónomos; Nekazaritza Ingeniarien Goi Mailako Eskola Teknikoa
    Los denominados contaminantes emergentes se caracterizan por su introducción continua en el medio ambiente con la particularidad de no ser eliminados fácilmente con los métodos convencionales. Los compuestos farmacéuticos representan una clase de este tipo de contaminantes debido a la gran demanda mundial y a su disposición inadecuada. Como una medida de calidad ambiental, en la Directiva 2013/39/UE se han introducido las disposiciones específicas y el seguimiento de los mismos debido a los posibles daños a la salud de los seres humanos y al potencial impacto ecológico. En la presente investigación se llevó a cabo el estudio de la degradación mediante fotocatálisis heterogénea de cuatro fármacos seleccionados por su amplio uso a nivel mundial: ibuprofeno, cafeína, diclofenaco y ácido salicilíco. La fotocatálisis forma parte de los procesos de oxidación avanzada (POAs) muy utilizados en la actualidad por ser una alternativa de tratamiento a los procesos químicos convencionales. En primer lugar se utilizaron dos óxidos de titanio como fotocatalizadores, que permitieron seleccionar las condiciones de cantidad de catalizador y concentración de las moléculas, adecuadas para lograr la mayor degradación de cada uno de los fármacos. Con estas condiciones se llevó a cabo la degradación catalítica para cada sistema empleando una arcilla modificada químicamente con Ti. El avance de la reacción se llevó a cabo por espectroscopia ultravioleta-visible. Los catalizadores empleados se caracterizaron por adsorción de N2 a -196 °C, difracción de rayos X, espectroscopia infrarrojo y análisis térmico.