The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Graham J Hutchings - One of the best experts on this subject based on the ideXlab platform.
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the activity and mechanism of Uranium Oxide catalysts for the oxidative destruction of volatile organic compounds
Catalysis Today, 2000Co-Authors: Stuart Hamilton Taylor, Graham J Hutchings, Catherine S Heneghan, Ian D HudsonAbstract:Uranium Oxide based catalysts have been investigated for the oxidative destruction of volatile organic compounds (VOCs) to carbon Oxides and water. The catalysts have been tested for the destruction of range of organic compounds at space velocities up to 70000 h-1. Destruction efficiencies greater than 99 can be achieved over the appropriate Uranium based catalyst in the temperature range 300-450°C. Volatile organic compounds investigated include benzene, butylcetane, cyclohexanone, toluene, methanol, acetylene, butane, chlorobutane and chlorobenzene. The catalysts are thermally stable, destroy low concentrations and mixtures of VOCs and the lifetime studies indicate that deactivation during oxidation of chlorinated VOCs did not occur. A temporal analysis of products (TAPs) reactor is used to investigate the mechanism of oxidation of VOCs by Uranium Oxide catalysts. Studies indicated that VOCs were oxidised directly to carbon Oxides on the catalyst surface. A combination of TAP pulse experiments with oxygen present and absent in the gas phase has indicated that the lattice oxygen from the catalyst is responsible for the total oxidation activity. This has been confirmed by studies using isotopically labelled oxygen which indicates that the catalyst operates by a redox mechanism.
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a temporal analysis of products study of the mechanism of voc catalytic oxidation using Uranium Oxide catalysts
Catalysis Today, 1999Co-Authors: Catherine S Henegha, Graham J Hutchings, Shane R Oleary, Stuart Hamilto Taylo, Vicki J Oyd, Ia D HudsoAbstract:A temporal analysis of products (TAP) reactor is used to investigate the mechanism of oxidation of volatile organic compounds by Uranium Oxide catalysts. Continuous flow studies indicated that butane, benzene and chlorobutane VOCs were oxidised to carbon Oxides and no partially oxidised products were observed. A combination of TAP pulse experiments with oxygen present and absent in the gas phase has indicated that the lattice oxygen from the catalyst is responsible for the total oxidation activity. This has been confirmed by studies using isotopically labelled oxygen. It is proposed that the catalysts operates by a redox mechanism utilising lattice oxygen and the high activity shown by U3O8 is due to the facile Uranium redox couple and the non-stoichiometric nature of the Oxide.
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Uranium Oxide based catalysts for the destruction of volatile chloro organic compounds
Nature, 1996Co-Authors: Graham J Hutchings, Catherine S Heneghan, Ian D Hudson, Stuart Hamilton TaylorAbstract:THE industrial release of hydrocarbons and chlorine-containing organic molecules into the environment continues to attract considerable public concern, which in turn has led to governmental attempts to control such emissions. The challenge is to reduce pollution without stifling economic growth1. Chlorine-containing pollutants are known to be particularly stable, and at present the main industrial process for their destruction involves thermal oxidation at 1,000° C, an expensive process that can lead to the formation of highly toxic by-products such as dioxins and dibenzofurans2. Catalytic combustion at lower temperatures could potentially destroy pollutants more efficiently (in terms of energy requirements) and without forming toxic by-products. Current industrial catalysts are based on precious metals that are deactivated rapidly by organochlorine compounds3. Here we report that catalysts based on Uranium Oxide efficiently destroy a range of hydrocarbon and chlorine-containing pollutants, and that these catalysts are resistant to deactivation. We show that benzene, toluene, chlorobutane and chlorobenzene can be destroyed at moderate temperatures (<400 °C) and industrially relevant flow rates.
Stuart Hamilton Taylor - One of the best experts on this subject based on the ideXlab platform.
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the activity and mechanism of Uranium Oxide catalysts for the oxidative destruction of volatile organic compounds
Catalysis Today, 2000Co-Authors: Stuart Hamilton Taylor, Graham J Hutchings, Catherine S Heneghan, Ian D HudsonAbstract:Uranium Oxide based catalysts have been investigated for the oxidative destruction of volatile organic compounds (VOCs) to carbon Oxides and water. The catalysts have been tested for the destruction of range of organic compounds at space velocities up to 70000 h-1. Destruction efficiencies greater than 99 can be achieved over the appropriate Uranium based catalyst in the temperature range 300-450°C. Volatile organic compounds investigated include benzene, butylcetane, cyclohexanone, toluene, methanol, acetylene, butane, chlorobutane and chlorobenzene. The catalysts are thermally stable, destroy low concentrations and mixtures of VOCs and the lifetime studies indicate that deactivation during oxidation of chlorinated VOCs did not occur. A temporal analysis of products (TAPs) reactor is used to investigate the mechanism of oxidation of VOCs by Uranium Oxide catalysts. Studies indicated that VOCs were oxidised directly to carbon Oxides on the catalyst surface. A combination of TAP pulse experiments with oxygen present and absent in the gas phase has indicated that the lattice oxygen from the catalyst is responsible for the total oxidation activity. This has been confirmed by studies using isotopically labelled oxygen which indicates that the catalyst operates by a redox mechanism.
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Uranium Oxide based catalysts for the destruction of volatile chloro organic compounds
Nature, 1996Co-Authors: Graham J Hutchings, Catherine S Heneghan, Ian D Hudson, Stuart Hamilton TaylorAbstract:THE industrial release of hydrocarbons and chlorine-containing organic molecules into the environment continues to attract considerable public concern, which in turn has led to governmental attempts to control such emissions. The challenge is to reduce pollution without stifling economic growth1. Chlorine-containing pollutants are known to be particularly stable, and at present the main industrial process for their destruction involves thermal oxidation at 1,000° C, an expensive process that can lead to the formation of highly toxic by-products such as dioxins and dibenzofurans2. Catalytic combustion at lower temperatures could potentially destroy pollutants more efficiently (in terms of energy requirements) and without forming toxic by-products. Current industrial catalysts are based on precious metals that are deactivated rapidly by organochlorine compounds3. Here we report that catalysts based on Uranium Oxide efficiently destroy a range of hydrocarbon and chlorine-containing pollutants, and that these catalysts are resistant to deactivation. We show that benzene, toluene, chlorobutane and chlorobenzene can be destroyed at moderate temperatures (<400 °C) and industrially relevant flow rates.
C. Ballouard - One of the best experts on this subject based on the ideXlab platform.
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Uranium metallogenesis of the peraluminous leucogranite from the Pontivy-Rostrenen magmatic complex (French Armorican Variscan belt): the result of long-term oxidized hydrothermal alteration during strike-slip deformation
Mineralium Deposita, 2018Co-Authors: C. Ballouard, Julien Mercadier, Michel Cuney, M. Poujol, E. Deloule, P. Boulvais, M. Cathelineau, J. M. BaeleAbstract:In the French Armorican Variscan belt, most of theeconomically significant hydrothermal U deposits are spatiallyassociated with peraluminous leucogranites emplacedalong the south Armorican shear zone (SASZ), a dextral lithosphericscale wrench fault that recorded ductile deformationfrom ca. 315 to 300 Ma. In the Pontivy-Rostrenen complex, acomposite intrusion, the U mineralization is spatially associatedwith brittle structures related to deformation along theSASZ. In contrast to monzogranite and quartz monzodiorite(3 < U < 9 ppm; Th/U > 3), the leucogranite samples arecharacterized by highly variable U contents (~ 3 to 27 ppm)and Th/U ratios (~ 0.1 to 5) suggesting that the crystallizationof magmatic Uranium Oxide in the more evolved facies wasfollowed by Uranium Oxide leaching during hydrothermal alterationand/or surface weathering. U-Pb dating of UraniumOxides from the deposits reveals that they mostly formed betweenca. 300 and 270 Ma. In monzogranite and quartzmonzodiorite, apatite grains display magmatic textures andprovide U-Pb ages of ca. 315 Ma reflecting the time of emplacementof the intrusions. In contrast, apatite grains from theleucogranite display textural, geochemical, and geochronologicalevidences for interaction with U-rich oxidized hydrothermalfluids contemporaneously with U mineralizingevents. From 300 to 270 Ma, infiltration of surface-derivedoxidized fluids leached magmatic Uranium Oxide from fertileleucogranite and formed U deposits. This phenomenon wassustained by brittle deformation and by the persistence ofthermal anomalies associated with U-rich granitic bodies.
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Multiple crust reworking in the French Armorican Variscan belt: implication for the genesis of Uranium-fertile leucogranites
International Journal of Earth Sciences, 2018Co-Authors: C. Ballouard, M. Poujol, Armin ZehAbstract:In the French Armorican Variscan belt, most of theeconomically significant hydrothermal U deposits are spatiallyassociated with peraluminous leucogranites emplacedalong the south Armorican shear zone (SASZ), a dextral lithosphericscale wrench fault that recorded ductile deformationfrom ca. 315 to 300 Ma. In the Pontivy-Rostrenen complex, acomposite intrusion, the U mineralization is spatially associatedwith brittle structures related to deformation along theSASZ. In contrast to monzogranite and quartz monzodiorite(3 < U < 9 ppm; Th/U > 3), the leucogranite samples arecharacterized by highly variable U contents (~ 3 to 27 ppm)and Th/U ratios (~ 0.1 to 5) suggesting that the crystallizationof magmatic Uranium Oxide in the more evolved facies wasfollowed by Uranium Oxide leaching during hydrothermal alterationand/or surface weathering. U-Pb dating of UraniumOxides from the deposits reveals that they mostly formed betweenca. 300 and 270 Ma. In monzogranite and quartzmonzodiorite, apatite grains display magmatic textures andprovide U-Pb ages of ca. 315 Ma reflecting the time of emplacementof the intrusions. In contrast, apatite grains from theleucogranite display textural, geochemical, and geochronologicalevidences for interaction with U-rich oxidized hydrothermalfluids contemporaneously with U mineralizingevents. From 300 to 270 Ma, infiltration of surface-derivedoxidized fluids leached magmatic Uranium Oxide from fertileleucogranite and formed U deposits. This phenomenon wassustained by brittle deformation and by the persistence ofthermal anomalies associated with U-rich granitic bodies.
Ian D Hudson - One of the best experts on this subject based on the ideXlab platform.
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the activity and mechanism of Uranium Oxide catalysts for the oxidative destruction of volatile organic compounds
Catalysis Today, 2000Co-Authors: Stuart Hamilton Taylor, Graham J Hutchings, Catherine S Heneghan, Ian D HudsonAbstract:Uranium Oxide based catalysts have been investigated for the oxidative destruction of volatile organic compounds (VOCs) to carbon Oxides and water. The catalysts have been tested for the destruction of range of organic compounds at space velocities up to 70000 h-1. Destruction efficiencies greater than 99 can be achieved over the appropriate Uranium based catalyst in the temperature range 300-450°C. Volatile organic compounds investigated include benzene, butylcetane, cyclohexanone, toluene, methanol, acetylene, butane, chlorobutane and chlorobenzene. The catalysts are thermally stable, destroy low concentrations and mixtures of VOCs and the lifetime studies indicate that deactivation during oxidation of chlorinated VOCs did not occur. A temporal analysis of products (TAPs) reactor is used to investigate the mechanism of oxidation of VOCs by Uranium Oxide catalysts. Studies indicated that VOCs were oxidised directly to carbon Oxides on the catalyst surface. A combination of TAP pulse experiments with oxygen present and absent in the gas phase has indicated that the lattice oxygen from the catalyst is responsible for the total oxidation activity. This has been confirmed by studies using isotopically labelled oxygen which indicates that the catalyst operates by a redox mechanism.
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Uranium Oxide based catalysts for the destruction of volatile chloro organic compounds
Nature, 1996Co-Authors: Graham J Hutchings, Catherine S Heneghan, Ian D Hudson, Stuart Hamilton TaylorAbstract:THE industrial release of hydrocarbons and chlorine-containing organic molecules into the environment continues to attract considerable public concern, which in turn has led to governmental attempts to control such emissions. The challenge is to reduce pollution without stifling economic growth1. Chlorine-containing pollutants are known to be particularly stable, and at present the main industrial process for their destruction involves thermal oxidation at 1,000° C, an expensive process that can lead to the formation of highly toxic by-products such as dioxins and dibenzofurans2. Catalytic combustion at lower temperatures could potentially destroy pollutants more efficiently (in terms of energy requirements) and without forming toxic by-products. Current industrial catalysts are based on precious metals that are deactivated rapidly by organochlorine compounds3. Here we report that catalysts based on Uranium Oxide efficiently destroy a range of hydrocarbon and chlorine-containing pollutants, and that these catalysts are resistant to deactivation. We show that benzene, toluene, chlorobutane and chlorobenzene can be destroyed at moderate temperatures (<400 °C) and industrially relevant flow rates.
Zhifang Chai - One of the best experts on this subject based on the ideXlab platform.
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template free synthesis and mechanistic study of porous three dimensional hierarchical Uranium containing and Uranium Oxide microspheres
Chemistry: A European Journal, 2014Co-Authors: Lin Wang, Ran Zhao, Congzhi Wang, Liyong Yuan, Chengliang Xiao, Shu Ao Wang, Xinwei Wang, Yuliang Zhao, Zhifang ChaiAbstract:A novel type of Uranium-containing microspheres with an urchin-like hierarchical nano/microstructure has been successfully synthesized by a facile template-free hydrothermal method with uranyl nitrate hexahydrate, urea, and glycerol as the Uranium source, precipitating agent, and shape-controlling agent, respectively. The as-synthesized microspheres were usually a few micrometers in size and porous inside, and their shells were composed of nanoscale rod-shaped crystals. The growth mechanism of the hydrothermal reaction was studied, revealing that temperature, ratios of reactants, solution pH, and reaction time were all critical for the growth. The mechanism study also revealed that an intermediate compound of 3UO(3)center dot NH3 center dot 5H(2)O was first formed and then gradually converted into the final hydrothermal product. These Uranium-containing microspheres were excellent precursors to synthesize porous Uranium Oxide microspheres. With a suitable calcination temperature, very uniform microspheres of Uranium Oxides (UO2+x, U3O8, and UO3) were successfully synthesized.
