Current status of the application of ionizing radiation to environmental protection: III. Sewage sludge, gaseous and solid systems (A review)

Пикaeв, A.К.

doi:10.1007/bf02762421

Cited by 10 publications

(3 citation statements)

References 53 publications

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“…Concepts for remediation, often subsumed under the label of “advanced oxidation processes” (AOP), have been developed along various lines, such as γ-irradiation of the soil ( , ); γ- or electron-beam (EB) irradiation of the water at various degrees of pollution ( − ); electrical discharge ( , ); UV/H 2 O 2 ( , ); O 3 /UV ( − ); O 3 /H 2 O 2 ( − ); light/metal oxide, usually in the form of UV/titanium dioxide ( , ) or ultrasound ( − ), and have been proposed, more or less convincingly, to offer solutions to these problems whenever the biodegradative approach, making use of the existing community of microorganisms that have become adapted to the particular situation, is impractical. In all of these AOP approaches, the reactive OH radical plays a decisive role.…”

Section: Introductionmentioning

confidence: 99%

Electron-Beam Treatment of Aromatic Hydrocarbons That Can Be Air-Stripped from Contaminated Groundwater. 1. Model Studies in Aqueous Solution

Mark

Schuchmann

et al. 2002

Environ. Sci. Technol.

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As a model for the electron-beam degradation of volatile aromatics (benzene, toluene, ethylbenzene, xylenes, BTEX) in groundwater strip gas, to be reported in Part 2, the gamma-radiolysis of benzene has been studied in aqueous solutions. Addition of *OH to the aromatic ring gives rise to hydroxycyclohexadienyl radicals which either dimerize or disproportionate. The various dimers undergo acid-catalyzed water elimination yielding biphenyl. Phenol is formed upon disproportionation directly, but also via dihydroxycyclohexadiene which subsequently undergoes acid-catalyzed water elimination. Co-radiolysis of benzene with nitrite generates *NO2 in addition to the hydroxycyclohexadienyl radical. These not only interact with one another (product: nitrobenzene via nitro-hydroxycyclohexadienes) but the *NO2 radical is also capable of abstracting cyclohexadienylic hydrogens. This reaction leads to the formation of 2- and 4-nitrophenol and to further nitrated products that were not identified. These are suggested to be formed in an analogous reaction of *NO2 with the hydroxycylohexadienyl dimers. The effect of O2 on these reactions and the relevance for the gas-phase radiolysis of BTEX is discussed.

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Section: Introductionmentioning

confidence: 99%

Electron-Beam Treatment of Aromatic Hydrocarbons That Can Be Air-Stripped from Contaminated Groundwater. 1. Model Studies in Aqueous Solution

Mark

Schuchmann

et al. 2002

Environ. Sci. Technol.

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“…As is seen from the experiments on the desorption of Hg(II) compounds from solid particles [30], an appreciable part of adsorbed mercury undergoes further chemical conversion into compounds HgO and HgS, which are insoluble under the usual temperatures. It should also be noted that, as a consequence of the small value of the equilibrium constants for the reactions HgO The electron-beam treatment of gas is one of the most promising methods of cleaning waste gases of solidfuel power plants from nitrogen and sulfur oxides [31,32]. The method is based on the obtaining in the gas, under the action of radiation, of small amounts of active components (atoms and radicals).…”

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confidence: 99%

Investigation of the Behavior of Mercury Compounds in Coal Combustion Products

Gerasimov¹

2005

J Eng Phys Thermophys

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The main mechanisms of transformation of mercury compounds in coal combustion products in the region of high temperatures have been analyzed. A kinetic model of the process of gas-phase oxidation of metal mercury vapors is proposed. The features of the behavior of the investigated compounds in systems of cleaning combustion products from harmful impurities have been considered.Mercury compounds are among the most toxic and long-lived microimpurities in the atmospheric air. Native sources of mercury emitted into the atmosphere are water surfaces, soils, plants, forest fires, volcanos, etc. and, according to the estimates of different authors, the total emission of mercury is about 3000 tons/year [1]. Among the anthropogenic sources of mercury compounds are industries, heat power engineering, and incineration of rubbish. The anthropogenic emission of mercury in Europe is about 600 tons/year. In the countries of Eastern Europe (including the European part of Russia), the release of mercury compounds into the atmosphere is mainly due to the operation of solid-fuel thermal power plants [2].Unlike the majority of metals forming small impurities in solid fuel, mercury is an extremely volatile element. Therefore, mercury compounds are present in solid-fuel combustion products before their release into the atmosphere practically completely in the gas phase. The further behavior of these toxic components of flue gases is determined by the processes of their photochemical oxidation in cloud drops and precipitation on the earth's surface near the emission source [3].The dominant forms of mercury in solid-fuel combustion products are vapors of metal mercury Hg 0 , as well as compounds of bivalent mercury Hg(II): HgCl 2 (g) and HgO(g, s) [4]. As the results of thermodynamic calculations show, the redistribution of mercury between different compounds varies over wide ranges and depends on the regime parameters of the process (initial fuel composition, temperature, pressure, etc.) [5,6].Because of the poor solubility of metal mercury vapors in water, removal of Hg 0 from combustion products is only possible upon its chemical conversion into readily soluble compounds of Hg(II). In the present paper, the main mechanisms of Hg 0 -Hg(II) conversion have been analyzed, a kinetic model of the process is proposed, and the features of the behavior of mercury compounds in systems of removing harmful impurities from solid-fuel combustion products have been considered.Thermodynamic Analysis of the Process. The content of mercury in power-generating coals varies from 0.01 to 1 mg/kg [7]. In the process of fuel combustion, mercury goes to the gas phase in the form Hg 0 . At an average content of this impurity in the initial fuel of 0.1 mg/kg, the Hg 0 concentration in combustion products is about 15 µg ⁄ nm 3 .The processes of further conversion of Hg 0 are rather complicated and consist of homogeneous and heterogeneous reactions of the gaseous components containing Hg and Cl atoms [8]. Among the methods of mathematical modeling of such proc...

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“…The treatment of industrial wastewater with electron beam is one of the actively studied subjects for the environment [16,17]. Electron beam irradiation treatment of the printing and dyeing wastewater has been considered to have some advantages over the conventional processes [18,19].…”

Section: Introductionmentioning

confidence: 99%

Removal of Dye from Textile Dyeing Wastewater by Using Oxidized Multiwalled Carbon Nanotubes

Shi

et al. 2011

AMR

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The batch removal of dye from textile dyeing wastewater by using nanooxides decorated multiwalled carbon nanotubes was studied under electron beam conditions. The effect of different nanooxides decorated multiwalled carbon nanotubes content and irradiation dosage was also investigated. The color removal efficiency was 94.9% in dose of 17.5kGy. The colour removal efficiency with Fe2O3 decorated multiwalled carbon nanotubes was similar to with TiO2 decorated multiwalled carbon nanotubues. The COD removal efficiency was 52.5% in the dose of 14.0kGy. When the irradiation dose of 17.5kGy, the COD removal efficiency was 98.2% with TiO2 decorated multiwalled carbon nanotubes.Overall, the study demonstrated that nanooxides decorated multiwalled carbon nanotubes can effectively remove color and COD from aqueous solution under irradiation.

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Current status of the application of ionizing radiation to environmental protection: III. Sewage sludge, gaseous and solid systems (A review)

Cited by 10 publications

References 53 publications

Electron-Beam Treatment of Aromatic Hydrocarbons That Can Be Air-Stripped from Contaminated Groundwater. 1. Model Studies in Aqueous Solution

Electron-Beam Treatment of Aromatic Hydrocarbons That Can Be Air-Stripped from Contaminated Groundwater. 1. Model Studies in Aqueous Solution

Investigation of the Behavior of Mercury Compounds in Coal Combustion Products

Removal of Dye from Textile Dyeing Wastewater by Using Oxidized Multiwalled Carbon Nanotubes

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