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Korili, Sophia A.

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https://academica-e.unavarra.es/handle/2454/49339

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Korili

First Name

Sophia A.

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Ciencias

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InaMat2. Instituto de Investigación en Materiales Avanzados y Matemáticas

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0000-0001-9086-4934

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2269

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Now showing 1 - 10 of 46

Open Access
Synthesis strategies of alumina from aluminum saline slags
(Elsevier, 2023) Grande López, Lucía; Vicente, Miguel Ángel; Korili, Sophia A.; Gil Bravo, Antonio; Ciencias; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Aluminum saline slags is a waste of the metallurgical industry that presents serious environmental problems since it needs very extensive areas for its disposal, the toxicity it causes in the atmosphere and groundwater, in addition to high transportation costs. The valorization of this residue by the synthesis of alumina, a compound widely used in the chemical industry, generates a high impact and great interest. In this work, the strategies for synthesizing alumina from aluminum saline slags are reviewed in a context of growing demand for this metal and environmental crisis. The first sections present the aluminum production processes, both from natural bauxite (primary process) and from the recycling of materials with a high aluminum content (secondary process); paying attention to the waste generated and what environmental problems they produce. The main investigations that have allowed to address the recovery of the waste generated are described below, focusing on the processes of recovery/extraction of the aluminum present in its composition. The aluminum in these residues can be found as a metal or forming other compounds such as simple or mixed oxides. Chemical processes are the most relevant, especially those that deal with the acid and alkaline extraction of the metal. The most important section of the work reports on the methods of synthesis of Al2O3, highlighting the methods of precipitation, sol-gel, hydrothermal synthesis, and combustion, among others. The work ends with a summary and conclusions section.
Open Access
Optimizing the removal of nitrate by adsorption onto activated carbon using response surface methodology based on the central composite design
(Taylor & Francis, 2020) Taoufik, Nawal; Elmchaouri, Abdellah; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias
This study sheds light on the adsorption process for the removal of nitrate ions from synthetic aqueous solutions. This contaminant pose a potential risk to the environment and can cause health effects including cancers and methemoglobinemia in infants. When the adsorption process is carried out, the effect by the several operating parameters such as initial nitrate concentration, pH, mass of activated carbon, and contact time becomes apparent. The essential process variables are optimized using response surface methodology (RSM) based on the central composite design (CCD) experiments. For this purpose 31 experimental results are required to determine the optimum conditions. The optimum conditions for the removal of nitrates is found to be: initial nitrate concentration = 15 mg/L; initial pH 4.0; mass of activated carbon = 25 mg, and contact time = 70 min. At these optimized conditions, the maximum removal of nitrates is found to be 96.59%.
Open Access
Photocatalytic degradation of trimethoprim on doped Ti-pillared montmorillonite
(Elsevier, 2019) González, Beatriz; Trujillano, Raquel; Vicente, Miguel Ángel; Rives, Vicente; Korili, Sophia A.; Gil Bravo, Antonio; Institute for Advanced Materials and Mathematics - INAMAT2
Montmorillonite pillared with titanium and doped with Cr3+ or Fe3+ has been tested for the photo-degradation of the antibiotic trimethoprim (trimethoxybenzyl-2,4-pyrimidinediamine) under different conditions, namely, in the dark or in UV light, with or without catalyst, finding excellent catalytic performance under photocatalytic conditions. The degradation by-products were preliminary analysed by mass spectrometry. The results suggested that the molecule broke in two halves, corresponding to its two existing rings. The process continued with the breakage of new fragments from the trimethoxybenzene half, these fragments later reacted with the methoxy groups in this part of the molecule, giving species with m/z values higher than that for the starting molecule, and with the breakage of new fragments.
Open Access
Evidence for the synthesis of La-hexaaluminate from aluminum-containing saline slag wastes: correction of structural defects and phase purification at low temperature
(Elsevier, 2021) Torrez Herrera, Jonathan Josué; Fuentes Ordóñez, Edwin Gustavo; Korili, Sophia A.; Gil Bravo, Antonio; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The synthesis of a lanthanum hexaaluminate from the aluminum extracted from a saline slag waste is presented for the first time. Briefly, a refluxing 2 M solution of HCl is used to extract the aluminum, giving 8.9 gAl/dm3 along with other metals in lower concentrations. This solution is used to synthesize the hexaaluminate by mixing with a stoichiometric amount of lanthanum nitrate. The results showed the formation of pure phase hexaaluminate at 1473 K, as well as predominance of the hexaaluminate phase at temperatures of 1273 and 1373 K. These results also indicate that the pure hexaaluminate phase can be obtained at a much lower temperature than when commercial aluminum solutions are used improving the applications as catalyst and thermal barrier material. It was also found that the presence of other metals in solution allows the structural problems and purity of the La-hexaaluminate phase to be corrected when working with stoichiometric ratios.
Open 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.
Open 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.
Open 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.
Open Access
Understanding the formation of Al13 and Al30 polycations to the development of microporous materials based on Al13-and Al30-PILC montmorillonites: a review
(Elsevier, 2021) Cardona Rodríguez, Yaneth; Gil Bravo, Antonio; Korili, Sophia A.; Zientziak; Institute for Advanced Materials and Mathematics - INAMAT2; Ciencias; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Hydrolysis of aluminum cations (Al3+), the third most abundant metal in the Earth’s crust, is considered relevant in many academic fields, including materials science and chemical engineering. AlIII -polycations and their different uses have also been widely studied, as reflected in the extensive literature in that field. This review summarizes some of those studies, from Al3+ hydrolysis to form Al13 ([Al13O4(OH)24(H2O)12]7+) and Al30 ([(Al30O8(OH)56(H2O)24)]18+) polycations and their specific use as pillaring agents for montmorillonite, which is the most commonly used clay mineral in Aluminum Pillared Interlayered Clays (Al-PILC) synthesis. The experimental conditions published over the years regarding the synthesis of both these AlIII-polycations, as well as the conditions employed to synthesize Al-PILC montmorillonite using Al13 and Al30 polycation solutions, are also summarized. This review highlights some of the findings that have made it possible to explain the formation of Al13- and Al30-PILC montmorillonites, and allow us to clearly understand their differences. Finally, the new tendencies in the development of these materials based on Al-PILC and the applications are also highlighted.
Open 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.
Open Access
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.