Diseño de materiales a base de TiO2 para aplicaciones fotocatalíticas medioambientales

RESUMEN: La contaminación y disponibilidad del agua y la crisis energética se han convertido en dos de los principales desafíos para la sociedad en un futuro cercano. Por lo tanto, existe una necesidad urgente de buscar tecnologías sostenibles para satisfacer las demandas de los seres humanos. En las últimas décadas, los procesos de oxidación avanzada (POAs) han atraído un gran interés debido a su versatilidad y sus amplias áreas de aplicación. Específicamente, la fotocatálisis heterogénea ha surgido como una alternativa factible ya que permite trabajar a temperatura ambiente y presión atmosférica, siendo el dióxido de titanio (TiO2) es uno de los fotocatalizadores más prometedores debido a que es abundante y económico. Sin embargo, presenta algunos inconvenientes que dificultan su aplicación comercial. Se hacen necesarios fotocatalizadores capaces de trabajar bajo luz visible y con bajas tasas de recombinación de los portadores de carga para la mejora de la tecnología de fotocatálisis. Con este objetivo, el óxido de grafeno y los metales nobles han sido empleados para mejorar la actividad limitada del TiO2 comercial. Por tanto, la presente tesis doctoral tiene como objetivo el diseño, síntesis y caracterización de materiales a base de TiO2 para el tratamiento de soluciones acuosas de ácido dicloroacético (DCA) y la producción fotocatalítica de hidrógeno, un prometedor vector energético, a partir de glicerol.ABSTRACT: Pollution and water scarcity and the energy crisis have become two of the main challenges for society in the near future. Therefore, there is urgent need to search for sustainable technologies to meet demands of human beings. Over the last decades, advanced oxidation processes (AOPs) have been attracting a great interest due to their versatility and potential areas of application. Specifically, heterogeneous photocatalysis has emerged as a feasible alternative since it allows working at room temperature and atmospheric pressure. Until now, titanium dioxide (TiO2) is one of the most promising photocatalyst because it is abundant and cost-effective. However, some drawbacks hinder its wider commercial application. Photocatalysts capable of working under visible light and with low recombination rates of charge carriers are necessary for the improvement of photocatalysis technology. With this objective, graphene oxide and noble metals have been selected to improve the limited activity of commercial TiO2. Therefore, this thesis aims at the design, synthesis and characterization of materials based on TiO2 for the treatment of aqueous solutions of dichloroacetic acid (DCA) and the photocatalytic production of hydrogen, a promising energy vector, from glycerol.This thesis was conducted at the Advanced Separation Processes Group in the Department of Chemical and Biomolecular Engineering at the University of Cantabria. This research was financially supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund through the projects: CTM2012-33917 “Advanced oxidation technologies for the improvement of landfill leachate treatment”, CTQ2012-31639 “New separation processes with kinetic control based on the use of functionalized materials”, CTM2015-69845-R “New developments in photocatalysis for environmental applications”, and CTQ2015-66078-R “Advanced separation applications. Modeling and experimental validation”. Paula Ribao has benefited from predoctoral research grant from University of Cantabria granted by resolution of January 11, 2016. Moreover, Paula Ribao has received a predoctoral mobility grant for short stays from University of Cantabria granted by resolution of April 27, 2017. Due to all of these, a warm thanks towards these institutions is extended