Publication: Desarrollo de sistemas bifuncionales "adsorbente-fotocatalizador" para la degradación de contaminantes en aire
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2018-09-11
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Universidad Complutense de Madrid
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Abstract
El impacto de la contaminación del aire sobre la salud y el medioambiente es unapreocupación importante en la sociedad actual. Los compuestos orgánicos volátiles llamadoscomúnmente por su acrónimo en inglés (VOCs), contribuyen a fenómenos atmosféricos tanimportantes como el smog fotoquímico. Además muchos de estos compuestos producen daños en lasvías respiratorias y son considerados carcinogénicos. Dentro de las tecnologías para el control de lacontaminación, la fotocatálisis heterogénea ha demostrado ser eficiente tanto en fase acuosa comoen fase gas. Esta tecnología se basa en la excitación de un semiconductor con energía de longitud deonda adecuada, para generar pares electrón/hueco. Estos son capaces de reaccionar dando lugar aespecies altamente oxidantes, involucradas en las reacciones de oxidación-reducción. Las principalesventajas de esta tecnología frente a otros procesos radican en que permite degradar mezclascomplejas de contaminantes, opera a temperatura ambiente y se pueden emplear lámparas de bajapotencia o luz solar natural como fuente de excitación. A pesar de que la mayoría de los estudiosfotocatalíticos publicados en la bibliografía están relacionados con la degradación de contaminantesen agua, el interés por la depuración de aire, tanto interior como exterior, es cada vez mayor. Por otrolado, la mayor parte de los estudios fotocatalíticos en aire se realizan en condiciones muy alejadas dela realidad, en reactores discontinuos y elevados tiempos de residencia.Aunque el TiO2 es el fotocatalizador por excelencia debido a sus propiedades, bajo precio,abundancia e inocuidad, en los últimos años se han abordado diferentes estrategias para promoversu eficiencia. Los sistemas fotocatalíticos bifuncionales basados en un adsorbente y unfotocatalizador conocidos por su acrónimo en inglés (APHs) son una familia de materiales queofrecen grandes posibilidades para el tratamiento de contaminantes. Estudios realizados con la participación de la Unidad FOTOAIR, han demostrado que los materiales híbridos basados ensepiolita y TiO2 consiguen aumentar la velocidad de reacción respecto al semiconductor de referencia, disminuyendo la formación de subproductos de reacción y favoreciendo la mineralización. La combinación de las propiedades fotocatalíticas del semiconductor con las propiedades del adsorbente permite obtener mejoras notables en la eficiencia fotocatalítica...
The impact of air pollution on the health and the environment is a major concern in today’ssociety. Volatile organic compounds (VOCs) contribute to important atmospheric phenomena such asthe photochemical smog. In addition, many of these compounds cause severe damage to therespiratory system and are considered carcinogenic. Among the existing technologies for thetreatment of these pollutants, heterogeneous photocatalysis has demonstrated to be an efficientprocess for the abatement of contaminants in air and water phases. Heterogeneous photocatalysis isbased on the oxidation of the compounds at semiconductor materials by using radiant energy ofsuitable wavelength. This technology allows the degradation of complex mixtures of pollutants,operates at room temperature and the photonic activation can be achieved by the radiation provide bylow power lamps or, more importantly, from a renewable energy source such as the sunlight. Althoughmost of the photocatalytic studies published in the literature deal with the degradation of pollutants inwater, the interest in the purification of air both at indoor and outdoor environments, is increasing inthe last years. Most photocatalytic studies in air have been carried out in conditions far from the onesneeded in real applications, e.g., high residence times and discontinuous reactors.Although TiO2 is the benchmark photocatalyst due to its high photocatalytic performance, lowprice, non-toxicity, and safety, different strategies have been approached to promote thephotocatalytic properties of this semiconductor. One emerging area of interest is related to thedevelopment of Adsorbent-Photocatalyst Hybrids (APHs), which are bifunctional materials based onthe combination of an adsorbent and a semiconductor phase. These materials can offer greatpossibilities for the photo-treatment of pollutants. Recent studies have shown that ceramic platesbased on magnesium silicate and TiO2 are able to increase the reaction rate of organochloridecompounds with respect to the reference semiconductor, reducing the formation of reaction byproductsand promoting the mineralization. The combination of the photocatalytic properties of thesemiconductor with the properties of the adsorbent allows a remarkable improvement of thephotocatalytic efficiency...
The impact of air pollution on the health and the environment is a major concern in today’ssociety. Volatile organic compounds (VOCs) contribute to important atmospheric phenomena such asthe photochemical smog. In addition, many of these compounds cause severe damage to therespiratory system and are considered carcinogenic. Among the existing technologies for thetreatment of these pollutants, heterogeneous photocatalysis has demonstrated to be an efficientprocess for the abatement of contaminants in air and water phases. Heterogeneous photocatalysis isbased on the oxidation of the compounds at semiconductor materials by using radiant energy ofsuitable wavelength. This technology allows the degradation of complex mixtures of pollutants,operates at room temperature and the photonic activation can be achieved by the radiation provide bylow power lamps or, more importantly, from a renewable energy source such as the sunlight. Althoughmost of the photocatalytic studies published in the literature deal with the degradation of pollutants inwater, the interest in the purification of air both at indoor and outdoor environments, is increasing inthe last years. Most photocatalytic studies in air have been carried out in conditions far from the onesneeded in real applications, e.g., high residence times and discontinuous reactors.Although TiO2 is the benchmark photocatalyst due to its high photocatalytic performance, lowprice, non-toxicity, and safety, different strategies have been approached to promote thephotocatalytic properties of this semiconductor. One emerging area of interest is related to thedevelopment of Adsorbent-Photocatalyst Hybrids (APHs), which are bifunctional materials based onthe combination of an adsorbent and a semiconductor phase. These materials can offer greatpossibilities for the photo-treatment of pollutants. Recent studies have shown that ceramic platesbased on magnesium silicate and TiO2 are able to increase the reaction rate of organochloridecompounds with respect to the reference semiconductor, reducing the formation of reaction byproductsand promoting the mineralization. The combination of the photocatalytic properties of thesemiconductor with the properties of the adsorbent allows a remarkable improvement of thephotocatalytic efficiency...
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Tesis de la Universidad Complutense de Madrid, Facultad de Ciencias Químicas, Departamento de Ingeniería Química, leída el 17-07-2017