Photocatalytic processes in the presence of titanium dioxide provide an interesting route to dest... more Photocatalytic processes in the presence of titanium dioxide provide an interesting route to destroy hazardous organic contaminants, being operational in the UV-A domain with a potential use of solar radiation. A preliminary evaluation of a photocatalytic process for water purification has been made to assess its effectiveness in reducing contaminant concentrations of drinking water standards. Studies reported in this paper also evaluate the performance of a low-cost compound parabolic concentrator (CPC) prototype built along this work and explore the feasibility of this concept as the basis for the solar photocatalytic oxidation facilities of water supplies. From our observations, a solar throughput value of 42 l/h m 2 for the low-cost CPC reactor tested at our facilities has been obtained. These calculations are based on the time required for the destruction of 500 g/l of selected pesticides to maximum permitted levels (0.1 g/l) and four-log inactivation of microorganisms. From the research performed, cost analyses have been made for a full-scale commercial system using the data available in this project. For a 500 m 2 facility, the estimated total costs for photocatalytic degradation is competitive with conventional technologies and estimated to be ca. 0.7 $/m 3 .
P I I : S 0038 -092X( 98 )00120 -0 All rights reserved. Printed in Great Britain Abstract-Solar p... more P I I : S 0038 -092X( 98 )00120 -0 All rights reserved. Printed in Great Britain Abstract-Solar photocatalytic oxidation processes (PCO) for degradation of water and air pollutants have recently received increasing attention. Some field-scale experiments have demonstrated the feasibility of using a semiconductor (TiO ) in solar collectors and concentrators to completely mineralize organic contaminants in 2 water and air. Although successful pre-industrial solar tests have been carried out, there are still discrepancies and doubt concerning process fundamentals such as the roles of active components, appropriate modelling of reaction kinetics or quantification of photoefficiency. Challenges to development are catalyst deactivation, slow kinetics, low photoefficiency and unpredictable mechanisms. The development of specific non-concentrating collectors for detoxification and the use of additives such as peroxydisulfate have made competitive use of solar PCO possible. The challenges and perspectives of solar driven PCO as illustrated in the literature and our own results in large solar field loops at the Plataforma Solar de Almeria and CIEMAT laboratories are described.
A new monolithic catalyst based on Pt/TiO 2 has been developed for the photocatalytic destruction... more A new monolithic catalyst based on Pt/TiO 2 has been developed for the photocatalytic destruction of traces of organic pollutants present in gaseous emissions. The in¯uence of both the raw materials used in the preparation of the support (titanias and magnesium silicates) and the nature of the doping phase (Pt or V 2 O 5 ) on the properties of the catalysts have been studied. Finally, a hydroxylated titania gel was selected as a catalyst precursor, a mixture of magnesium silicates as inorganic binders and platinum as the doping phase. The developed monolithic catalyst can be described as composed of platinum dispersed over the surface of titania-anatase particles, which were intimately mixed with the ®brous magnesium silicate.
Las mismas asignaciones de variables ocurrirán para ambas entradas del usuario, porque el operado... more Las mismas asignaciones de variables ocurrirán para ambas entradas del usuario, porque el operador de extracción de flujo >> ignora todos los espacios en blanco, incluye ndo los CRLF. Nota: Es posible usar el flujo cin con el operador >> para leer varias variables como parte de un enunciado sencillo. Por ejemplo, el enunciado: cin >> registro1 >> registro2 >> registro3;
Photocatalytic processes in the presence of titanium dioxide provide an interesting route to dest... more Photocatalytic processes in the presence of titanium dioxide provide an interesting route to destroy hazardous organic contaminants, being operational in the UV-A domain with a potential use of solar radiation. A preliminary evaluation of a photocatalytic process for water purification has been made to assess its effectiveness in reducing contaminant concentrations of drinking water standards. Studies reported in this paper also evaluate the performance of a low-cost compound parabolic concentrator (CPC) prototype built along this work and explore the feasibility of this concept as the basis for the solar photocatalytic oxidation facilities of water supplies. From our observations, a solar throughput value of 42 l/h m 2 for the low-cost CPC reactor tested at our facilities has been obtained. These calculations are based on the time required for the destruction of 500 g/l of selected pesticides to maximum permitted levels (0.1 g/l) and four-log inactivation of microorganisms. From the research performed, cost analyses have been made for a full-scale commercial system using the data available in this project. For a 500 m 2 facility, the estimated total costs for photocatalytic degradation is competitive with conventional technologies and estimated to be ca. 0.7 $/m 3 .
P I I : S 0038 -092X( 98 )00120 -0 All rights reserved. Printed in Great Britain Abstract-Solar p... more P I I : S 0038 -092X( 98 )00120 -0 All rights reserved. Printed in Great Britain Abstract-Solar photocatalytic oxidation processes (PCO) for degradation of water and air pollutants have recently received increasing attention. Some field-scale experiments have demonstrated the feasibility of using a semiconductor (TiO ) in solar collectors and concentrators to completely mineralize organic contaminants in 2 water and air. Although successful pre-industrial solar tests have been carried out, there are still discrepancies and doubt concerning process fundamentals such as the roles of active components, appropriate modelling of reaction kinetics or quantification of photoefficiency. Challenges to development are catalyst deactivation, slow kinetics, low photoefficiency and unpredictable mechanisms. The development of specific non-concentrating collectors for detoxification and the use of additives such as peroxydisulfate have made competitive use of solar PCO possible. The challenges and perspectives of solar driven PCO as illustrated in the literature and our own results in large solar field loops at the Plataforma Solar de Almeria and CIEMAT laboratories are described.
A new monolithic catalyst based on Pt/TiO 2 has been developed for the photocatalytic destruction... more A new monolithic catalyst based on Pt/TiO 2 has been developed for the photocatalytic destruction of traces of organic pollutants present in gaseous emissions. The in¯uence of both the raw materials used in the preparation of the support (titanias and magnesium silicates) and the nature of the doping phase (Pt or V 2 O 5 ) on the properties of the catalysts have been studied. Finally, a hydroxylated titania gel was selected as a catalyst precursor, a mixture of magnesium silicates as inorganic binders and platinum as the doping phase. The developed monolithic catalyst can be described as composed of platinum dispersed over the surface of titania-anatase particles, which were intimately mixed with the ®brous magnesium silicate.
Las mismas asignaciones de variables ocurrirán para ambas entradas del usuario, porque el operado... more Las mismas asignaciones de variables ocurrirán para ambas entradas del usuario, porque el operador de extracción de flujo >> ignora todos los espacios en blanco, incluye ndo los CRLF. Nota: Es posible usar el flujo cin con el operador >> para leer varias variables como parte de un enunciado sencillo. Por ejemplo, el enunciado: cin >> registro1 >> registro2 >> registro3;
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