Kinetics and Mechanism of Wet-Air Oxidation of Nuclear-Fuel-Chelating Compounds

Bachir, Souley; Barbati, Stéphane; Ambrosio, M.; Tordo, Paul

doi:10.1021/ie000818t

Cited by 16 publications

(5 citation statements)

References 18 publications

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“…250 This technique was particularly used in the 1990s to characterize • OH radicals in the photooxidation of chlorophenols in the presence of H 2 O 2 , 251 in TiO 2 −H 2 O 2 −photocatalytic systems for the decomposition of p-toluenesulfonic acid 252 or alkylphenols, 253 in TiO 2 − water−oxygen systems for the mineralization of p-cresol, 254 or to demonstrate the implication that • OH produced in Fenton system originates exclusively from hydrogen peroxide. 255 More recently, intermediates in wet air oxidation, including • OH, were successfully identified from real effluent containing nuclear-fuel-chelating compounds 256 or model effluent containing cellulose. 257…”

Section: Detection Of • Oh Radicals By Electron Paramagnetic Resonancementioning

confidence: 99%

Environmental Implications of Hydroxyl Radicals (^•OH)

et al. 2015

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The hydroxyl radical ((•)OH) is one of the most powerful oxidizing agents, able to react unselectively and instantaneously with the surrounding chemicals, including organic pollutants and inhibitors. The (•)OH radicals are omnipresent in the environment (natural waters, atmosphere, interstellar space, etc.), including biological systems where (•)OH has an important role in immunity metabolism. We provide an extensive view on the role of hydroxyl radical in different environmental compartments and in laboratory systems, with the aim of drawing more attention to this emerging issue. Further research on processes related to the hydroxyl radical chemistry in the environmental compartments is highly demanded. A comprehensive understanding of the sources and sinks of (•)OH radicals including their implications in the natural waters and in the atmosphere is of crucial importance, including the way irradiated chromophoric dissolved organic matter in surface waters yields (•)OH through the H2O2-independent pathway, and the assessment of the relative importance of gas-phase vs aqueous-phase reactions of (•)OH with many atmospheric components. Moreover, considering the fact that people spend so much more time in dwellings than outside, the impact of the reactivity of indoor hydroxyl radicals on health and well-being is another emerging research topic of great concern.

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Section: Detection Of • Oh Radicals By Electron Paramagnetic Resonancementioning

confidence: 99%

Environmental Implications of Hydroxyl Radicals (^•OH)

et al. 2015

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“…Among the existing alternatives, catalytic wet air oxidation (CWAO) is interesting for the treatment of industrial wastewaters due to its intrinsic efficiency in the reduction of chemical oxygen demanding species, by means of an oxidizing source under relatively mild conditions (125-220°C, 5-50 bar) in the presence of an adequate catalyst. Recent examples of application include herbicide removal [1], pulp and paper mill effluent [2], printing and dyeing wastewaters from the textile industry [3], alkaloid factory wastewater [4], and wastewaters from nuclear fuel processing plants [5]. Although, some very active homogeneous catalysts can be used, such as copper [6] and iron salts [7], they need to be separated from the treated effluent, which is a drawback for industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Carbon supported platinum catalysts for catalytic wet air oxidation of refractory carboxylic acids

et al. 2005

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Carbon supported platinum (1% wt) catalysts were prepared by the incipient wetness impregnation method and by organometallic chemical vapor deposition. Catalyst characterization was carried out by means of adsorption and thermogravimetric techniques, and by electron microscopy. The catalyst with higher metal dispersion was produced by incipient wetness impregnation. The catalysts were tested in the catalytic wet air oxidation (200°C and 6.9 bar of oxygen partial pressure) of aqueous solutions containing low molecular weight (C 2 to C 4 ) carboxylic acids. Significant conversions (greater than 60% over 2 h) and 100% selectivity towards water and non-carboxylic acid products were observed for both systems. The initial reaction rate was used to compare the performance of the two catalytic materials and direct correspondence to the metal dispersion was found. No metal leaching was observed during reaction and no significant deactivation occurred in three successive catalytic oxidation runs. A kinetic model based on the Langmuir-Hinshelwood formulation was applied and the results were analyzed in terms of a heterogeneously catalyzed free radical mechanism.KEY WORDS: catalytic wet air oxidation (CWAO); carbon supported platinum catalysts; incipient wetness impregnation; organometallic chemical vapor deposition (OMCVD)

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“…WAO of organic pollutants is generally described by a free-radical chain reaction mechanism in which the induction period to generate a minimum radical concentration is of great significance [6][7][8][9]. In the most detailed studied reaction in WAO, in the oxidation of phenol water solution during the induction period, practically no change was observed in phenol concentration.…”

Section: Kinetic Mechanism Of Waomentioning

confidence: 99%

Wet Air Oxidation of Aqueous Wastes

Tungler¹,

Szabados²,

Hosseini³

2015

Wastewater Treatment Engineering

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Wet air oxidation W"O is a key technology in the disposal of industrial and agricultural process wastewaters. It is often used coupled with activated sludge treatment at a wastewater treatment plant WWTP as preliminary conversion of toxic and/or non-biodegradable components. The process is based on a high temperature and pressure reaction of the oxidizable materials in water with air or oxygen, in most cases in a bubble column reactor. The oxidation is a chain type radical reaction. The intensification of this technology is possible with the application of homogeneous and heterogeneous catalysts, recently non-thermal radical generating methods UV/H O , ozonization, Fenton type processes gathered ground also. The most frequent use of the process is in sludge treatment and oxidation of spent caustic of refineries or ethylene plants.

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Kinetics and Mechanism of Wet-Air Oxidation of Nuclear-Fuel-Chelating Compounds

Cited by 16 publications

References 18 publications

Environmental Implications of Hydroxyl Radicals (^•OH)

Environmental Implications of Hydroxyl Radicals (^•OH)

Carbon supported platinum catalysts for catalytic wet air oxidation of refractory carboxylic acids

Wet Air Oxidation of Aqueous Wastes

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Kinetics and Mechanism of Wet-Air Oxidation of Nuclear-Fuel-Chelating Compounds

Cited by 16 publications

References 18 publications

Environmental Implications of Hydroxyl Radicals (•OH)

Environmental Implications of Hydroxyl Radicals (•OH)

Carbon supported platinum catalysts for catalytic wet air oxidation of refractory carboxylic acids

Wet Air Oxidation of Aqueous Wastes

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Product

Resources

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Environmental Implications of Hydroxyl Radicals (^•OH)

Environmental Implications of Hydroxyl Radicals (^•OH)