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Hirota, Koichi; Kojima, Takuji
Bulletin of the Chemical Society of Japan, 78(9), p.1685 - 1690, 2005/09
Times Cited Count：7 Percentile：31.75(Chemistry, Multidisciplinary)Decomposition behavior under electron-beam irradiation was examined for polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) isomers in incinerator gases. Significant decomposition was obtained for all PCDD isomers over the investigated absorbed doses, which was resulted from oxidation reactions with OH radicals yielded by electron-beam irradiation. In the case of PCDFs, specific isomers having symmetrical structures such as 1, 2, 8, 9-, 2, 3, 7, 8-, and 3, 4, 6, 7-TeCDFs were yielded through the dechlorination of PeCDF isomers. Thermal electrons probably played a role in the dechlorination of PeCDF isomers.
Kojima, Takuji
Shinku, 47(11), p.789 - 795, 2004/11
When flue gas/off gas is irradiated by EB, many free radicals such as OH and active oxygen atom are formed from major components of air: namely nitrogen, oxygen, water and carbon dioxide ecules. The similer reaction can be achieved using UV light and plasma-discharging, but ionizing radiations produce such free radicals at higher density. Such radiation-induced radicals react efficiently with air pollutants, SOx and NOx in coal/oil combustion flue gas at thermal power plants, dioxins in waste incineration flue gas and volatile organic compounds (VOC) even in very low concentration and decompose them into non-toxic substances or change them to removable substances. R & D on EB treatment of flue gas/off gas done in JAERI on the basis of this principle process, as an example, is described in the present paper.
Kojima, Takuji
Shokubai, 46(3), p.248 - 253, 2004/04
The present paper describes research and development on purification technology using electron beams for flue/odd gases containing pollutants: removal of sulfate oxide and nitrogen oxide from flue gases of coal/oil combustion power plants, decomposition of dioxins in waste incineration flue gas, and decomposition/removal of toxic volatile organic compounds from off gas.
Takigami, Machiko; Arai, Hidehiko*; Hirota, Koichi; Taguchi, Mitsumasa; Hakoda, Teruyuki; Kojima, Takuji
Kankyo Kagaku, 14(1), p.13 - 23, 2004/03
The Japan Atomic Energy Research Institute undertook a pilot scale electron beam decompostion of dioxins in the flue gases from the municipal solid waste incinerator at the Takahama Clean Center. The conventional method, following the Japan Industrial Standards (JIS) method, takes 2 weeks at least to extract and purify dioxins from the flue gases for analysis by GC/MS. However, using a carbon adsorbent, the time required for the extraction of dioxins was shortened from 16 to 2.5 hours. Further improvements in the clean up process enabled the overall time to be reduced to less than a half of that rquired by the JIS method. Using this simplified method allows analysts, who are not practiced in the pretreatment of flue gases, to prepare samples for dioxin analysis by GC/MS. The sampling and pretreatment of the flue gases can, with this process, be completed within 4 days with accuracy comparable to JIS method.
Hirota, Koichi; Hakoda, Teruyuki; Taguchi, Mitsumasa; Takigami, Machiko; Kim, H.; Kojima, Takuji
Environmental Science & Technology, 37(14), p.3164 - 3170, 2003/07
Times Cited Count：43 Percentile：65.45(Engineering, Environmental)The electron-beam technology was applied to reduce polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) in flue gases from the municipal solid waste incinerator (MSWI) at a temperature of 200
C. More than 90% of PCDD/Fs in a flue gas of 1000 m
N/h was decomposed at a dose of 14 kGy. The decomposition of PCDD/Fs was probably initiated through reactions with OH radicals, followed by the dissociation of ether bond (-C-O-C-), the cleavage of aromatic rings, and dichlorination. The dechlorination of the higher dechlorinated PCDF homologues produced the lower chlorinated ones, which led to lower decomposition efficiency of PCDF than that of PCDD.
Kojima, Takuji; Hirota, Koichi; Taguchi, Mitsumasa; Hakoda, Teruyuki; Takigami, Machiko
Proceedings of 25th JAIF-KAIF Seminar on Nuclear Industry, p.193 - 201, 2003/00
The electron beam technology for decomposition/elimination of dioxin contained in flue gas has been developed using real waste gas of 1,000 mN/h released from the municipal solid waste incineration facility at 200
C. The decomposition efficiency, the ratio of toxic equivalent dioxin concentration before and after EB irradiation to doses above 15kGy is higher than 90%, which clears the regulation limit in the Japanese special measures of dioxin release. The chemical process of dioxin decomposition was studied and low-toxicity of irradiated gas was confirmed in terms of endocrine disrupter influence.
Hirota, Koichi; Hakoda, Teruyuki; Taguchi, Mitsumasa; Takigami, Machiko*; Kojima, Takuji
Proceedings of 9th International Conference on Radiation Curing (RadTech Asia '03) (CD-ROM), 4 Pages, 2003/00
The flue gas from a municipal solid waste incinerator (MSWI) was irradiated with electron beams to destroy polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). A flue gas of 1,000 m/h N for the irradiation was obtained at 200C from a main gas stream of the MSWI. The decomposition efficiencies of PCDD/Fs were increased with absorbed dose and reached 90% at a dose of 14 kGy. The reaction mechanisim for PCDD/Fs was also considered.
Yamauchi, Toshihiko; Ito, Shinichi*; Minehara, Eisuke
Technical Digest on 4th Pacific Rim Conference on Lasers and Electro-Optics (CLEO/Pacific Rim 2001), p.I_148 - I_149, 2001/00
The decomposition of dioxin analogues by infrared (IR) laser irradiation includes thermal destruction and multiple-photon dissociation. It is important for the decomposition to choose the laser wavelength which is highly absorbed. The thermal decomposition takes place by the irradiation of the low IR laser power. Considering the model of thermal decomposition, it is discussed that the adjacent water vapor assists the decomposition (dechlorination) of dioxin analogues in addition to the thermal decomposition by the direct laser absorption.
Arai, Hidehiko
Hoshasen To Sangyo, 0(69), p.36 - 37, 1996/00
no abstracts in English
