Development of nanostructured carbon-based catalysts for photocatalytic conversion of CO2 into added-value fuels

Nowadays, energy shortages, carbon resource shortages, and global warming are the major challengs. The usage of photocatalysis to realize the conversion of CO2 into added-value fuels can alleviate the above problems. As a visible light photocatalyst without metal components, g-C3N4 has unique electronic structure, high catalytic activity, good chemical and thermal stability, which has caused wide attention. This article mainly summarized the basic properties and structure of g-C3N4. Besides, we introduced the commonly used preparation methods and modification methods of g-C3N4, and prospects the application of g-C3N4.<br /

Materiales bidimensionales semiconductores: aplicaciones en fotocatálisis

En el siguiente Trabajo de fin de grado se han desarrollado materiales semiconductores con el objetivo de mejorar la actividad fotocatalítica. Esto se ha estudiado en la reacción de hidrogenación del disulfuro de molibdeno (MoS2), que previamente se sintetiza por un método hidrotermal. Además, se ha llevado a cabo el dopaje de dicho material con metales (níquel y cobalto) a diferentes ratios y la heterounión con otro semiconductor mediante molienda mecánica de alta energía (ball milling). Por último, combinando ambas partes, se ha elijdo el ratio de metales más adecuado y el porcentaje de MoS2 óptimo para la heterounión y se ha realizado un estudio de la reacción de hidrogenación analizando si se ha conseguido mejorar la respuesta fotocatalítica.<br /

Ordered mesoporous silica monoliths: synthesis, preparation and potential applications

The work carried out was focused on the preparation of rigid porous silica monoliths, in order to investigate applications as controlled drug release matrices. All work was based on the hexagonally-ordered mesoporous SBA-15 materials, and monoliths were obtained by gel-casting procedures. SBA-15 powder was successfully synthesized and characterized using SEM and TEM imaging, nitrogen adsorption and small-angle X-ray diffraction. Synthesis yielded fibrous SBA-15 particles with diameters between 4,5 and 7,5µm and lengths between 75 and 105µm, and highly ordered cylindrical pores arranged in a hexagonal fashion with a diameter between 5,6 and 6,9 nm. Functionalization of SBA-15 powder was carried out using (3-Aminopropyl)triethoxysilane as a functionalizing agent, in order to test functionalization effects on drug release, and to prepare more stable monoliths. Monoliths were prepared using gel-casting procedures; a suspension of polyacrylamide precursors and powder SBA-15 was centrifuged in a glass mold, and polymer hardening and further removal of the polymer template yielded stable monoliths exhibiting a bimodal pore structure confirmed by intrusion characterization. Macroscopic dimensions of the monoliths were 3mm in diameter and approximately 6 mm in length, with macropores around 3 µm and the characteristic mesopores of SBA-15. Monoliths were also functionalized using (3-Aminopropyl)triethoxysilane. Drug loading for drug delivery experiments was carried out by placing as-synthesized and functionalized SBA-15 powders and monoliths in direct contact with a solution of a model antibiotic, namely cefuroxime sodium salt. Functionalized powders yielded the highest loads, followed by unmodified powders, modified monoliths and with as-synthesized monoliths exhibiting the lowest loads. Drug release experiments were focused on release of cefuroxime from as-synthesized and amino-functionalized SBA-15 powders and monoliths. Monoliths exhibit an initial burst release that was attributed to antibiotic loaded in the macroporous reservoirs, while a more controlled release was obtained from the powder counterparts

Desarrollo de nuevos sistemas de captura y recuperación de aerosoles nanoparticulados presentes en ambientes ocupacionales

El presente Trabajo Fin de Grado se enfoca en el desarrollo de sistemas de captura y recuperación de aerosoles nanoparticulados basados en captadores húmedos empleando sistemas de retención de chorro de líquido (“jet mixer”) para obtener una suspensión líquida de las nanopartículas presentes en la fase aerosol. El postratamiento mediante diferentes métodos servirá para la eliminación sin riesgos de nanomateriales potencialmente dañinos. Asimismo, el sistema permitirá la recuperación y reciclado de nanopartículas de alto valor añadido mediante procedimientos de recogida y estabilización de las suspensiones acuosas producidas. Con este objetivo, se ha diseñado un sistema que permite la aerosolización de materiales nanoparticulados (SiO2, TiO2, ZnO y Fe3O4) y su posterior captura en fase líquida mediante sistemas que ponen en contacto ambas fases. Se ha estudiado la eficacia de captura en función de la naturaleza y características de los nanomateriales, de las condiciones de operación, de la concentración de la corriente de recirculación, de la disposición del sistema de captura y de los métodos utilizados para generar el aerosol. Además se ha monitorizado la calidad del aire a la salida de sistema midiendo la concentración de partículas y su distribución de tamaños en fase aerosol, así como el empleo de técnicas avanzadas de análisis de nanomateriales (por ejemplo, DLS y TEM) para la caracterización de las suspensiones de partida, de los aerosoles y de las nanopartículas capturadas

Análisis del impacto medioambiental y ocupacional de nanopartículas aerosolizadas en escenarios controlados.

Nanotechnology has become indispensable in the daily life. Nanomaterials are present in a lot of products, such as cloths, cosmetics, food industry and medicines among others. In the last decades, the production of nanomaterials has increased and so the exposure to such nanomaterials to workers and even customers. Moreover, it would be necessary to distinguish the ENMs from natural nanomatter that is already in the environment. In order to do that, labelling techniques have been used, particularly fluorescent labelling applied in SiO2 nanoparticles, which is one of the most used ENMs (mobile phones, cosmetics...etc.). Most of the researches are focused on the study of harmful ENMs uptaken through respiratory or ingestion route, but, what about the harm effects through cutaneous route? In this project surface contamination has been assessed using fluorescent Ru(phen)3:SiO2 NPs. Not only that, but it is necessary to catalogue these engineered nanomaterials (ENMs) and test the environmental, health and safety impact. Once ENMs are released into the environment, they suffer several abiotic and biotic interactions so it is not possible to know their fate and disposition. In this project, the toxicity of Ru(phen)3:SiO2 NPs have been tested in Chamydomonas reinhardtii; and aging process have been assessed within a case study focused on Ebro River basin physicochemical properties