High-energy irradiation of chlorinated hydrocarbons

Matthews, Stephen M.; Boegel, A.J.; Eccles, S.F.; Homann, S.G.; Rice, D.W.; Loftis, J.A.; Jovanovich, M. C.; Caufield, R.A.; Mincher, Bruce J.; Meikrantz, D.H.; Murphy, Richard J.; Gresham, Garold L.; Connoly, M. J.

doi:10.1007/bf02034899

Cited by 13 publications

(2 citation statements)

References 3 publications

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“…For TCE in groundwater, the study of radiation decomposition has been undertaken as a potential technology. These applications with ionizing radiation demonstrated the direct decomposition of TCE in water by γ ray irradiation, , as well as the decomposition of gas-phase TCE stripped from the contaminated water by electron beam (EB) irradiation. − These experiments were performed under fixed concentrations of TCE.…”

Section: Introductionmentioning

confidence: 99%

Decomposition Mechanism for Electron Beam Irradiation of Vaporized Trichloroethylene−Air Mixtures

Hakoda¹,

Hirano²,

Fujiyama³

et al. 1999

J. Phys. Chem. A

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Decomposition of trichloroethylene (TCE) in electron beam irradiation was examined in order to get information on treatment of industrial off-gas. Air containing vaporized TCE was sealed into a glass vessel and irradiated with an electron beam. The concentration of TCE exponentially decreased with dose (air-absorbed energy). The doses necessary to decompose 90% of input TCE molecules had a value of 3.6 kGy independent of an initial concentrations ranging from 50 to 1800 ppmv. Between G values of decomposition and initial concentrations, the following equation was obtained:. The equation shows that concentrations of Cl radicals remained constant at 6.3 × 10 -4 ppmv (at 298 K and 1 bar) independent of concentrations of TCE and products under a dose rate of 2.1 kGy/s. Termination reactions in the decomposition mechanism for EB irradiation of TCE and tetrachloroethylene (PCE) were also clarified on the basis of the relation of G value of decomposition and the initial concentrations. Dichloroacetyl chloride, which was identified as a primary product, was decomposed and oxidized to give CO and CO 2 . Phosgene was also identified as a primary product. From the proportion of DCAC to COCl 2 concentrations, a branching ratio was calculated to be 5.3 in the Cl radical chain reaction of TCE. Formation of HCl and/or Cl 2 was analyzed and the collection of the products from the gas phase was examined with alkaline solution. The effect of water (400-25 000 ppmv) on decomposition efficiency was examined. The decomposition efficiencies had the same value as that in dry air.

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Section: Introductionmentioning

confidence: 99%

Decomposition Mechanism for Electron Beam Irradiation of Vaporized Trichloroethylene−Air Mixtures

Hakoda¹,

Hirano²,

Fujiyama³

et al. 1999

J. Phys. Chem. A

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“…The decomposition of PCB with gamma radiolysis has been studied by many groups. [7][8][9][10][11][12][13][14][15][16] An important purpose of their previous studies was to find effective ways to decompose the oil with high PCB concentration. For this reason, some scavenger substances or solvents were added to PCB oil to investigate how the additives affect the PCB decomposition.…”

Section: Introductionmentioning

confidence: 99%

An Approach to Reuse of PCB-Contaminated Transformer Oil Using Gamma Radiolysis

Tajima

Hasegawa

Horioka

2008

Journal of Nuclear Science and Technology

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The radiolytic decompositions of low-concentration polychlorinated biphenyls (PCB) and 1,2,4trichlorobenzene (TCBz) in a transformer oil have been studied using a 60 Co gamma ray irradiation facility. Significant decompositions of PCB and TCBz were observed in the oil at tens of kGy absorbed dose without any additive. We derived the required dose for KC500 decomposition in transformer oil using a power function, which indicates that oil with lower PCB concentration needs less dose to treat PCB wastes. We also observed that the gamma radiolyses of PCB and TCBz did not affect each other; the decompositions of PCB and TCBz proceed independently. Both PCB concentration analysis and total chlorine mass concentration analysis indicated that most dechlorinated chlorine atoms react to generate other chlorine compounds in the oil. We found that the gamma radiolysis without additional compounds in the oil can be a useful way of reusing PCB-contaminated transformer oil.

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Radiolytic decomposition of environmental contaminants and site remediation using an electron accelerator

Matthews¹,

Boegel²,

Loftis³

1993

Remediation Journal

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Halogenated and nonhalogenated hydrocarbon contaminants are currently found in natural waterways, groundwater, and soils as a result of spills and careless disposal practices. The development of proper treatment methodologies for the waste streams producing this environmental damage is now a subject of growing concern. A significant number of these waste stream compounds are chemically stable and are thus resistant to environmental degradation. Numerous researchers have investigated the use of ionizing radiation to decompose chlorinated hydrocarbons in diverse matrices and have proposed various free‐radical‐induced reaction mechanisms. This article is divided into two sections. First, we present data on experimentally measured, radiolytically induced decomposition of hazardous wastes and toxic substances using accelerator‐generated bremsstrahlung sources and gamma radiation from cobalt‐60. Data are presented on the radiolytically induced reduction in concentration of volatile organic compounds (VOCs) dissolved in water and in air, polychlorinated biphenyls (PCBs) dissolved in oil, high explosives dissolved in groundwater, and chemical weapon surrogates. The results of these studies suggest the potential use of ionizing radiation as a method of hazardous waste treatment. The second section of this article describes the technical aspects of a field‐scale radiolytic decomposition site cleanup demonstration using an electron accelerator. A portable, commercially available electron accelerator was set up at the Lawrence Livermore National Laboratory's (LLNL's) Site 300, a Superfund site, where vacuum extraction wells were removing trichloroethylene (TCE) vapor from a ground spill into the unsaturated soil zone. The accelerator was retrofitted into the existing vacuum extraction system such that the extracted TCE‐containing vapor passed through the accelerator beam for treatment. The concentration of TCE in the vapor was reduced by an amount dependent on the accelerator beam power. Production of reaction products in the vapor was measured as a function of absorbed dose.

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High-energy irradiation of chlorinated hydrocarbons

Cited by 13 publications

References 3 publications

Decomposition Mechanism for Electron Beam Irradiation of Vaporized Trichloroethylene−Air Mixtures

Decomposition Mechanism for Electron Beam Irradiation of Vaporized Trichloroethylene−Air Mixtures

An Approach to Reuse of PCB-Contaminated Transformer Oil Using Gamma Radiolysis

Radiolytic decomposition of environmental contaminants and site remediation using an electron accelerator

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