Obtención de hidrógeno a partir de biogás mediante catalizadores derivados de hidrotalcita

270 páginas, 78 tablas y 135 figurasEl objetivo de este trabajo ha sido el desarrollo de catalizadores derivados de la estructura hidrotalcita, que permitan la obtención de hidrógeno a partir de biogás mediante la reacción de reformado de metano con dióxido de carbono. Se han considerado tres variables a estudiar en el diseño de catalizadores: el contenido en lantano, la temperatura de calcinación y la relación molar Mg/Al. Tanto los precursores, como los catalizadores sintetizados a partir de ellos, fueron caracterizados por diversas técnicas físico-químicas para determinar la influencia que cada una de esas variables ejerce sus propiedades composicionales, texturales y estructurales. Los catalizadores fueron evaluados en la reacción de reformado de metano con dióxido de carbono en diversas condiciones de reacción, estudiando el comportamiento de cada uno de ellos en función de sus propiedades físico-químicas. Con el catalizador que presentó mejores prestaciones en cuanto a actividad, selectividad y estabilidad (LaHT3), se llevó a cabo un estudio de la influencia de diversas variables de operación (velocidad espacial, temperatura de reacción, composición de la alimentación) con objeto de optimizar las condiciones de reacción. Finalmente, se llevaron a cabo ensayos de larga duración y posterior caracterización para evaluar la estabilidad y resistencia a la desactivación.Peer reviewe

Obtención de hidrógeno a partir de biogás mediante catalizadores derivados de hidrotalcita

Tesis doctoral inédita, leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada. Fecha de lectura: 26-06-201

Формирование модели системы воспитания в школе на основе интеграции общего и дополнительного образования (из опыта работы)

Trabajo presentado en la European Hydrogen Energy Conference - EHEC, celebrada en Sevilla (España) del 12 al 14 de mayo de 2014.There is a growing interest in the development of power sources that use renewable fuels and reduce emission of pollutants. This interest is justified by the heightening concern about environmental degradation, energy security as well as the possible exhaustion of the fossil fuel resources. One example is the use of biogas (mainly composed by CH4 and CO2) which is generated from anaerobic digestion of sewage or wastewater [1]. In order to produce hydrogen from this renewable gas, it is necessary a reforming step. There are two alternatives: 1) carbon dioxide reforming (DR: CH4 + CO2 2H2 + 2CO) and 2) steam reforming (SR: CH4 + H2O 3H2 + CO). The first reaction has two drawbacks: the deactivation of the catalyst due to carbon deposition [2] and the participation of reverse water-gas-shift (RWGS: H2 + CO2 H2O + CO) which decreases the amount of the produced hydrogen. On the other hand, steam reforming is the most extended way to produce hydrogen from CH4, but it is necessary to eliminate the CO2 from the feed. Since previous studies [3] had reported good results when La-promoted catalysts, obtained from hydrotalcite-like precursor calcination, were used in dry reforming of methane, this catalyst will be used for these tests. The aim of this work is to study the influence of H2O addition over dry reforming and the addition of CO2 over steam reforming using a La-promoted catalyst obtained from hydrotalcite-like precursor.Financial support from Comunidad de Madrid (DIVERCELCM, S2009/ENE-1475) is gratefully acknowledged.Peer Reviewe

Photoactive nano-confined Pt in titania nanotubes (Pt-TiNT) via microwave-assisted flow synthesis

Pt-TiNT with PtO nanoparticles dispersed within the lumen and interlayer spaces of titania nanotubes (TiNT) were prepared by a new process involving titanate nanosheets (TiNS) synthesis in an optimized microwave-assisted flow reactor, followed by ion-exchange with a Pt precursor, before triggering the titanate layer rolling to trap the Pt precursor clusters inside the titania nanotubes, followed by a thermal treatment. TEM, XRD, and Raman analyses confirm the total conversion of TiO2 into TiNS in 15 min at 120 °C and 4 bar, and the TiNS transformation into 181 nm-long TiNT with 10 and 6 nm outer and inner diameter, respectively. The 2% Pt-TiNT comprises 0.7 nm PtO clusters (according to XPS), causing slight distortions of the interlayer spaces, while a few larger 2–3 nm Pt clusters reside within the lumen. As a result, Pt-TiNT is 14-fold more active than TiNT for visible light (400–780 nm) photocatalytic oxidation of diclofenac under 2136 μW·cm−2 irradiation, and>1000-fold better than the uncatalyzed photoconversion reaction under 100 mW·cm−2 artificial solar lighting. In addition, nano-confinement of PtO clusters narrowed the bandgap of the TiNT, which, combined with its excellent absorptivity to harvest light, allowed a broader spectral range of photon energies to activate the photocatalyst.11 página

Pyrolysis-catalytic dry (CO2) reforming of waste plastics for syngas production: Influence of process parameters

Catalytic dry (CO2) reforming of waste plastics was carried out in a two stage, pyrolysis-catalytic reforming fixed bed reactor to optimise the production of syngas (H2 + CO). The effects of changing the process parameters of, catalyst preparation conditions, catalyst temperature, CO2 input rate and catalyst:plastic ratio were investigated. The plastics used was a mixture of plastics simulating that found in municipal solid waste and the catalyst used was Ni-Co-Al2O3. The results showed that changing each of the process conditions investigated, all significantly influenced syngas production. An increase of 17% of syngas production was achieved from the experiment with the catalyst prepared by rising-pH technique compared to preparation via the impregnation method. The optimum syngas production of 148.6 mmolsyngas g−1swp was attained at the catalytic dry reforming temperature of 800 °C and catalyst:plastic ratio of 0.5. The increase of CO2 input rate promoted a higher yield of syngas

Lifestyle Evolution And Peroxidase Diversity In Agaricales As Revealed By Comparative Genomics

Descripción de 1 páginas de la comunicación oral presentada en Oxizymes2022 10th edition of the international “Oxizymes” meeting. Siena, Italy, July 5-8, 2022Basidiomycetes of the class Agaricomycetes have developed complex enzymatic machineries that allow them to decompose plant polymers, including lignin. Within this group, saprotrophic Agaricales are characterized by an unparalleled diversity of habitats and lifestyles in comparison with fungi from other orders. With the aim of shedding light on the evolution of lignocellulose-decaying lifestyles in Agaricales we conducted a comparative analysis of 52 Agaricomycetes genomes [1]. This study revealed that Agaricales possess a large diversity of hydrolytic and oxidative enzymes. Surprisingly, computer-assisted gene-family evolution analysis of these enzymes revealed that a few oxidoreductase families showed significantly higher evolutionary rates. Based on these gene families we reconstructed the lifestyles of the ancestors that led to the extant lignocellulose-decomposing Agaricomycetes. According to this, we determined that changes in the oxidative enzymatic toolkit of ancestral Agaricales correlate with the evolution of their ability to grow not only on wood, but also on leaf and grass litter and decayed wood. In this context, the aboye families were analyzed and special attention was paid to peroxidases as a central component of the enzymatic toolkit of saprotrophic Agaricomycetes responsible for lignin degradation. We identified a widespread presence of new ligninolytic peroxidase types in Agaricales, some of them not previously identified in this order, and others also not found in woodrottingPolyporales and other orders of Agaricomycetes. Peroxidase evolution was analyzed in Agaricomycetes by ancestral sequence reconstruction and several major evolutionary pathways were unveiled. The study of the newly identified peroxidases will provide insight into their role in the lignin degradation process. In fact, these studies have already been initiated with the expression and characterization of the first lignin peroxidase identified in Agaricales. [1] Ruiz-Dueñas FJ, Barrasa JM, Sánchez-García M, Camarero S, Miyauchi S, Serrano A, et al., 2021, Mol Biol Evol, 38, 1428-1446.Projects/contracts BI02017-86559-R, BI02015-7369-JIN, AGL2014-55971-R, NSFgrant-1457721 , CEFOX-031 B0831 S, PIE-201620E081 , ANR-11-LABX-0002-01 , US-DOE-DE-AC02-05CH11231N