Dpto. Ciencias - Zientziak Saila [desde mayo 2018 / 2018ko maiatzetik]
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Browsing Dpto. Ciencias - Zientziak Saila [desde mayo 2018 / 2018ko maiatzetik] by browse.metadata.doctorateProgram "Kimika Sintetiko eta Industrialeko Doktoretza Programa (ED 99/2011)"
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Publication Open Access Layered double hydroxides from aluminum saline slags applied in adsorption and photocatalysis processes for the removal of emerging pollutants(2020) Santamaría Arana, Leticia; Gil Bravo, Antonio; Korili, Sophia A.; Ciencias; Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa; Gobierno de Navarra / Nafarroako GobernuaThe objective of the work studied here was to synthesize Layered Double Hydroxides (LDH) with aluminum extracted from saline slags and test their function once calcined into adsorbents/catalysts for use in the removal of emerging contaminants (pharmaceutical compounds) from aqueous media.Two different techniques for the removal of contaminants were tested, adsorption and photocatalysis. In the present work, a new procedure for the recovery of aluminum present in saline slags generated during the secondary recycling processes of aluminum as adsorbent/photocatalyst of diclofenac and salicylic acid, as examples of emerging contaminants, has been reported. Results obtained have been extensively analyzed throughout the present study.Publication Embargo Removal of emerging pollutants in water through adsorption and catalytic processes using pillared clays synthesized from aluminum saline slags(2022) Cardona Rodríguez, Yaneth; Gil Bravo, Antonio; Korili, Sophia A.; Ciencias; Zientziak; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaIn this work, the aluminum was extracted from the saline slags using both ways the alkaline and the acidic one. Those extracts were used as precursors in the synthesis of Pillared Clays (PILC) obtaining pillared structures from the acidic extract (Al-PILCAE) and from the alkaline one (Al-PILCBE). The parameters in the synthesis of those PILC were studied characterizing the solids obtained with the purpose to optimize the synthesis process and choose the solids with the better characteristics. The solids chosen were studied as adsorbents and catalytic supports for the removal of three emerging pollutants from water: 2,6-dichlorophenol (2,6-DCP), triclosan (TCS), and bisphenol A (BPA). The adsorptive and catalytic behavior was compared with both the raw clay used in their synthesis (montmorillonite – Mt) and with a PILC synthesized by the conventional method using an aluminum commercial salt as the precursor (Al-PILCCM). The first two sections of this thesis focus on the theory related to the subject. First Chapter (I) refers to PILC, their synthesis, the parameters involved in this, and their importance and impact on the properties of the solid obtained. This chapter collected the studies related to this field, trying to understand the formation of the polycations that make possible the synthesis of PILC. The Second Chapter (II) is related to water pollution and the techniques used to eliminate pollutants from the aquatic environment. This chapter focused on the use of the adsorption process, and the use of PILC as adsorbents for organic pollutants, collecting the studies which have used them for this purpose. The next four chapters (Chapter III to Chapter VI) are related to the results and analysis of the results of the experimental part developed in this work. The first two of them (Chapter III and Chapter IV) are related to the synthesis of the porous clay-based materials and their use as adsorbents, and the next two (Chapter V and Chapter VI) to their use in photocatalysis. Chapter Three (III) corresponds to the synthesis of PILC from the saline slag and their evaluation as adsorbents in batch mode. The parameters involved in the synthesis process were evaluated, characterizing every time the synthesized solids to confirm that the pillaring process was successful. The synthesis process which resulted in solids with better characteristics was chosen for every one of both extracts: alkaline (Al-PILCBE) and acidic (Al-PILCAE). Those PILC were evaluated as adsorbents to remove 2,6-DCP, BPA, and TCS from water, in batch mode. The resulting adsorption capacities were compared with Mt and Al-PILCCM. Additionally, the reuse of the intercalating agent sequentially to synthesize Al-PILC as the reuse of the initial Al-PILC synthesized as adsorbent also was studied. It is necessary to highlight that this is the first time that a porous material is synthesized from saline slag using both extracts, alkaline, and acid. The annex in this document is related to this part of the study. The results obtained in the optimization of the synthesis of PILC using saline slag gave, as a result, a methodology that synthesized PILC with improved textural characteristics compared with those prepared through the conventional method. This methodology was evaluated using a commercial salt as the precursor and the results confirmed that the solids obtained using this had improved textural properties than using the conventional methodology. For this reason, due to the novelty of the methodology found, the technical information about the invention was disclosed in a patent application (202130047) as can be seen in the annex section. Chapter Four (IV) corresponds to the study of the three Al-PILC (Al-PILCAE, Al-PILCBE, and Al-PILCCM) as adsorbents in fixed bed column systems for the removal of TCS. In addition to the breakthrough curves, the adsorption of TCS adsorption in this system was optimized for its use in Solid Phase Extraction (SPE) by Response Surface Methodology using a Box–Behnken Design (RSM-BBD). Fixed-bed column studies are usually carried out to consider the possible application of the adsorbents in water purification processes, however, those studies can be made on a small scale to propose new materials to improve methodologies and routinary techniques used in the laboratory, including the sample preparation methodologies such as SPE. This study, for the first time, used chemometric tools to optimize the adsorption of TCS in fixed bed column by Al-PILC to use it in SPE. This is another way to support the research related to water pollution with EP. The low concentrations of EP in water sources can be lower than the Limit of Detection (LOD) and Limit of Quantitation (LOQ) of the analytical techniques necessary to evaluate those. It makes necessary a pre-concentration step prior to their determination and quantification. For this reason, the study and proposal of new sorbents that can be used in preparation techniques such as SPE for the determination and quantification of EP in water are relevant. Chapter Five (V) corresponds to the use and comparison of Mt and the three Al-PILC as catalytic supports for the removal of 2,6-DCP, TCS, and BPA from water through photocatalytic degradation using both VIS and UV light irradiation. TiO2/catalysts were synthesized by wet impregnation through stirring followed by calcination. Different loads of titanium were studied, and the characterization of the solids was carried out by several techniques. Finally, the photoproducts present in the solutions at the end of the process were evaluated by High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS). Additionally, since this chapter is the first related to catalysis, it complements the theoretical information shown in chapter two, listing those studies which have used clays and PILC in catalytic photodegradation processes. The novelty of this work lies in the use of Al-PILC synthesized from aluminum saline slags as catalytic supports and the evaluation of visible light irradiation for this process. Finally, Chapter Six (VI) corresponds to the use and comparison of Mt and the three Al-PILC as catalytic supports for the removal of 2,6-DCP, TCS, and BPA from water by Fenton and Photo-Fenton like processes. Fe(III)/TiO2/ catalysts with different titanium and iron loads were evaluated in single-component solutions and in an equimolar mixture. All catalysts were characterized by several techniques and the by-products for every pollutant were identified during the reactions by HPLC-MS. A degradation pathway was suggested for every pollutant based on the by-products identified during the reactions. The originality of this work is related to the fact of analyzing the process in both single and mixture components systems, using Al-PILC synthesized from aluminum saline slags as catalytic supports.Publication Embargo Synthesis and application of lanthanum aluminate perovskites obtained from aluminum saline slags as catalysts for dry reforming of methane and other environmental uses(2024) Muñoz Alvear, Helir Joseph; Gil Bravo, Antonio; Korili, Sophia A.; Ciencias; Zientziak; Universidad Pública de Navarra / Nafarroako Liburutegi PublikoaIn this work, the aluminum was successively extracted from saline slags using an acidic medium (HCl or citric acid). The aluminum solutions obtained were used as precursors in the synthesis of lanthanum aluminate perovskite supports (LaAlO3), and various synthesis methods, including MOF-gel precursor, Pechini, and modified citrate, were evaluated to obtain the perovskite. The parameters in the synthesis of lanthanum aluminate were studied, and the physicochemical properties of the resulting functional materials were characterized, with the purpose to optimize the synthesis process and choose the most promising materials. The chosen materials were evaluated, either as catalytic supports or as catalysts, for the dry reforming of methane or the degradation of carbofuran (CBF) in water doped with synthetic dissolved natural organic matter (NOM). The catalytic behavior was compared with that of catalysts prepared by conventional methods and using commercial aluminum saline. The first two chapters of this thesis correspond to the introduction and focus on the theory related to the subject. The First Chapter (I) refers to lanthanum aluminate perovskite, its physicochemical parameters, synthesis methods, and some of its applications. This chapter focuses on the review of studies from the past ten years related to all the synthesis methods employed in the preparation of lanthanum aluminate. It discusses the synthetic challenges, advantages, and limitations associated with these methods, as well as the most significant catalytic applications. The Second Chapter (II) is related to Ni-perovskites-based catalysts for the dry reforming of methane. This chapter delves into the thermodynamic and kinetic aspects of the DRM, highlighting that the properties of A and B can affect catalytic performance. It discusses recent advancements in the substituting of the B cation to enhance catalytic efficiency through synergistic effects. Similarly, the substitution of cation A is explored for its ability to control acid- base properties and the consequent impact on coke formation and deposition. The chapter also reviews progress in improving the low textural properties of perovskites, either directly or by deposition of the perovskites on a support. Finally, new lines of research focused on softening DRM reaction conditions and promoting the process at lower temperatures are also highlighted. The next three chapters (Chapter III to Chapter V) are related to the results and analysis of the experimental part developed in this work. Chapter III is related with a novel and simple strategy developed for synthesizing the pure perovskite phase of lanthanum aluminate (LaAlO3). This involves the calcination of a highly porous, dry MOF precursor gel, which is prepared using commercial precursors, and its subsequent application in the dry reforming of methane. This study revealed that the textural properties of the materials can be modulated by the solvothermal treatment time. Additionally, it identified the main factors that contribute to enhancing the catalytic performance in the dry reforming of methane (DRM) using the Ni/LaAlO3 catalyst. Chapter IV corresponds to the first synthesis of nickel-modified lanthanum aluminate (Ni/LaAlO3) perovskite catalysts using aluminum extracted from saline slag via acid leaching with HCl or citric acid. Three preparation methods (Pechini, modified citrate, and metal–organic gel) were evaluated to obtain the pure lanthanum aluminate (LaAlO3) phase. This study also investigated the effects of several factors, with some variations observed depending on the methodology used. The most promising materials were evaluated as catalytic supports for Ni active sites in the dry reforming of methane. The catalytic performance of the catalysts was compared with a reference catalyst prepared by a conventional method and using commercial aluminum salt. The annex in this document is related to this part of the study. Given the novelty of preparing lanthanum aluminate perovskite from HCl- and citric acid-extracted aluminum from saline slag, and due to the resulting enhancement in the physicochemical properties of the final functional materials, a patent application has been submitted (details provided in the annex). Chapter V corresponds to the first synthesis of LayAl1–xCuxO3–δ perovskite catalysts using Al extracted from saline slag residue (previously extracted with HCl). This study investigates the effect of parameters such as the La/Al molar ratio during the synthetic process. The best catalyst was used to optimize the degradation of carbofuran (CBF) in water doped with synthetic dissolved natural organic matter (NOM) using the Fenton-like catalytic wet peroxide oxidation (CWPO) approach. Lastly, this work investigates the optimal conditions for maximizing pesticide degradation. Finally, Chapter VI corresponds to the general conclusions that can be obtained from this work.