Desarrollo, Producción e Innovación en la Investigación científica
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Item Optimization of the synthesis of SBA-3 mesoporous materials by experimental desing.(Univesidsad Tecnológica Nacional., 2015) Ponte , María Virginia; Rivoira , Lorena Paola; Cussa , jorgelina; Martínez , María Laura; Beltramone , Andrea Raquel; Anunziata , Oscar Alfredo; Anunziata , Oscar Alfredo; Anunziata; Cussa , jorgelina; Rivoira , Lorena PaolaSBA-3 mesoporous materials are characterized by hexagonal regular arrangements of channels with diameters >2 nm, high specific surface areas and high specific pore volumes. In the work reported herein, experimental design-response surface methodology (RSM) is used to model and optimize the synthesis conditions for SBA-3 mesoporous materials. In this study, we evaluate the influences of surfactant/silica source molar ratios, aging times, temperature and pH on the synthesis of SBA-3 mesoporous materials by analyzing the XRD intensities pertaining to the [100] signal. Response surfaces were obtained using the BoxeBehnken design, and the combination of reaction parameters was optimized. By applying statistical methodology, higher levels of the objective function (XRD intensities pertaining to the [100] signal) were obtained using cetyltrimethylammonium bromide (CTAB)/tetraethyl orthosilicate (TEOS) molar ratios of 0.07 and 0.16, HCl/TEOS molar ratios of 8 and 11, reaction temperatures of 35 and 45 ◦C and aging times of 12e24 h. The mesoporous SBA-3 samples obtained were characterized using small-angle X-ray powder diffraction (XRD), BET, FTIR and 29Si NMR-MAS, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).Item Direct Synthesis of ordered mesoporous carbon as support of Ir-Catalyst and its application in hydrodenitrogenation of indole.(Univesidsad Tecnológica Nacional., 2018) Ledesma, Brenda Cecilia; Juárez , Juliana María; Beltramone, Andrea Raquel; Juárez , Juliana MaríaAn ordered mesoporous carbon (OMC) modified with titania was prepared using a novel and shorter synthesis method. OMC was successfully synthesized by the carbonization of the silica/TEOT/triblock copolymer/sucrose composite in the presence of sulfuric acid. This novel material was modified with the incorporation of nanoparticles of Iridium. Structural and textural characterization of the catalyst was performed by means of N2 adsorption, XRD, UV–Vis–DRS, Raman spectroscopy, XPS, TEM and H2 Chemisorption. The characterization results indicated that the textural and structural properties of the support synthesized by the short time method are comparable with the properties of the support prepared by the hard template method. Ir-Ti-OMC catalyst obtained by short time synthesis was active and selective in the hydrogenation of indole. Main advantage of the present study is the reduction of time and cost in the synthesis of the new material and the applicability for HDT reactions.Item Multiple-wall carbon nanotubes obtained with mesoporous material decorated with caria-zirconia.(Univesidsad Tecnológica Nacional, 2020) Rodríguez , Miguel Angel; Anunziata , Oscar Alfredo; Beltramone, Andrea Raquel; Juárez , Juliana María; Juárez , Juliana María; Anunziata , Oscar AlfredoIn this work, Ceria-Zirconia on ordered Santa Barbara mesoporous silica (Ce-Zr-SBA-15), has been used directly as a catalyst for the synthesis of carbon nanotubes (CNTs) through Chemical Vapor Deposition (CVD). In addition to cerium oxide, it contains zirconium oxide nano crystallites, which act as catalysts for carbon nanostructures. The catalytic performance of this material was evaluated for the decomposi- tion of ethanol at 900 °C, with N2 flow. The carbon decomposed from absolute ethanol diffuses through the surface of the nanostructured catalytic material and precipitates in the form of MWCNT structures, which could be identified by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), showing average diameters of 30–35 nm.Item Multiple-wall carbon nanotubes obtained with mesoporous material decorated with ceria-zirconia(2020) Rodríguez, Miguel Angel; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel; Martínez, María LauraIn this work, Ceria-Zirconia on ordered Santa Barbara mesoporous silica (Ce-Zr-SBA-15), has been used directly as a catalyst for the synthesis of carbon nanotubes (CNTs) through Chemical Vapor Deposition (CVD). In addition to cerium oxide, it contains zirconium oxide nano crystallites, which act as catalysts for carbon nanostructures. The catalytic performance of this material was evaluated for the decomposition of ethanol at 900 °C, with N2 flow. The carbon decomposed from absolute ethanol diffuses through the surface of the nanostructured catalytic material and precipitates in the form of MWCNT structures, which could be identified by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), showing average diameters of 30–35 nm.Item Mesopore carbón starch with acid properties: synthesis and characterization(2020) Martínez, María Laura; Anunziata, Oscar A.We have shown that a promising material with acidic properties can be successfully prepared from starch mesoporous carbon (SMC), functionalized with sulfated zirconia. The process of assembling P123, starch, zirconia, and silicon synthesized Zr-modified ordered mesoporous carbon. SMC and Zr-SMC were characterized by BET for their texture properties and, using Scanning Electron Microscopy (SEM), their morphology. Acidic properties were acquired by programmed thermodesorption of ammonia (NH3 TPD). These studies show that the Zr-SMCs material is mainly composed of mesopores with an average pore size of approximately 3.5 nm, high surface area and pore volume, and has medium to strong acidity properties.Item Multiple-wall carbón nanotubes obtained with mesoporous material decorated with cerio-zirconium(2020) Martínez, María Laura; Anunziata, Oscar A.In this work, Ce-Zr-SBA-15 has been used directly as a catalyst for the synthesis of multi-vall carbon nanotubes (MWCNT) through Chemical Vapor Deposition (CVD). In addition to cerium oxide, it contains zirconium oxide Nano crystallites, which act as catalysts for carbon nanostructures. The catalytic performance of this material was evaluated for the decomposition of ethanol at 900 °C, with N2 flow. The structural characterization of the resulting catalyst was carried out by means of SEM and XRD. The decomposed carbon of absolute ethanol diffuses through the surface of the nanostructured material and precipitates in carbon structures called multiple-walled nanotubes, which could be visualized/detected/identified by TEM, showing diameters of the carbon nanotubes that range from 15 to 25 nm.Item Green hydrogen from catalytic ammonia decomposition(2021) Gómez Costa, Marcos B.; Juárez, Juliana M.; Anunziata, Oscar A.Ir/γ-alumina catalysts for decomposition of ammonia were prepared by Iridium ion exchange procedure, onto γ-alumina synthesized by sol-gel method. In order to determine the physical and chemical properties we used X ray diffraction (XRD) analysis, Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nuclear magnetic resonance (NMR-MAS). The samples displayed the characteristic band at 1620 cm-1 corresponds to a N-H bending of ammonia adsorbed on electron-acceptor sites, and the characterization by pyridine adsorption and desorption to determine the presence of Lewis acid sites, with absence of Brønsted sites, showing higher acid strength than commercial sample used as reference. The analysis of particle size and morphology reveal uniformity, with tendency to a spheroid aspect and smaller to 3 μm of diameter. The 27Al NMR-MAS test, allowed determining the tetrahedral and octahedral aluminum presence in both samples, where the higher proportion of octahedral Al in γ-alumina synthesized by us, is correlated toward the greater electron acceptor acid sites. The designed method was effective for Ir/γ-alumina catalysts synthesis. The surface area was 150 and 260 m2/g for the commercial sample and the alumina prepared by and us, and after the Ir incorporation (10-18% w/w in both samples), they surfaces were reduced approximately 5.4-8.8% and 4.3-7.2% respectively. XRD analyses show the absence of maximums at 28º and 34.7º 2 corresponding to iridium oxide, indicating a high efficiency of the reduction treatment, increasing the active sites for the specific reaction of ammonia decomposition. The distribution of the Ir crystallites determined by XRD and TEM indicated that, the samples prepared by ion exchange method produced smaller Iridium clusters than by impregnation procedure of alumina sample, with higher surface area and greater anchorage sites. According to preliminary catalytic tests, the Ir/γ-alumina catalysts prepared by a novel method showed higher activity to ammonia decomposition to N2 and green H2.Item ZSM-5 fast synthesis employing soluble starch as template(2017) Bonetto, Luciana; Renzini, María Soledad; Saux, Clara; Pierella, Liliana BeatrizSolid catalysts with a zeolitic framework were synthesized in the ZSM-5 (MFI) topology employing tetrapropyl ammonium hydroxide (TPAOH) as structure directing agent and soluble starch as template in order to be employed in biomass revalorization reactions. It should be noted that starch is a soluble, biodegradable, low cost and nontoxic polymeric carbohydrate obtained from agricultural raw materials. Starch is employed in thissynthesis processfor pores generation and crystal connection to produce a material with MFI morphology type. ZSM-5 is a medium pore material from the pentasil zeolites group. The traditional synthesis procedure [1] takes around 10 days to obtain the MFI structure. In this new procedure, ZSM-5 type material is obtained by a hydrothermal treatment but in a shorter crystallization time. The effect of time on structure and cristallinity was studied. Zeolite synthesis was done employing sodium aluminate (NaAlO2) as aluminum source, tetraethyl orthosilicate (TEOS) as silicon source, TPAOH and distilled water. The solution was aged at 80 °C for 210 minutes under vigorous stirring. Ethanol produced from TEOS hydrolysis was evaporated and a clear gel was obtained. Then, different starch quantities dissolved in aqueous solutions were incorporated and further stirred for 30 minutes at the same temperature. The result suspension was hydrothermally treated at 140 °C in a Teflon lined stainless steel autoclave under static conditions. Crystallization time was varied between 96, 48 and 24 hours and the obtained material was washed with distilled water and dried at 110 °C for 24 hours. Finally, the solid were desorbed under N2 flow (20 ml/min) at 500 °C and further calcined at the same temperature for 8 hours in order to remove the carbonized starch and the organic structure directing agent trapped in the crystals. According to the crystallization time, samples were named as MFI-96, MFI-48 and MFI 24, respectively. The obtained samples were characterized by X Ray Diffraction (XRD), BET and Scanning Electron Microscopy to confirm structure, crystallinity and surface area. From XRD patterns high crystallinity and MFI structure were confirmed, indicating the successful crystallization in short time when soluble starch was added in the synthesis gel. Surface areas calculated from BET were similar to that obtained for traditional ZSM-5 (approximately 360 m2 /g). The so far synthesized and characterized materials were tested as catalysts for peanut shells valorization reactions to obtain platform molecules for the fine chemical industry.