Elucidation of degradation mechanism of dioxins during mechanochemical treatment.
Model dioxin compounds 4-chlorobiphenyl (4CB), octa-chlorodibenzo-p-dioxin (OCDD), and octachlorodibenzofuran (OCDF) were degraded by a mechanochemical (MC) process that involved milling with calcium oxide by use of a planetary ball mill. The degradation of 4CB produced mainly chloride ions and biphenyl, with the chlorine removal efficiency reaching about 100%. Biphenyl was transformed into terphenyls, quaterphenyls, cyclohexylbenzene, and bicyclohexyl through polymerization and hydrogenation reactions. Measurements of chloride ions after MC treatment of OCDD and OCDF showed about 100% dechlorination of both compounds; tetra- to heptachlorinated dibenzo-p-dioxins/furans (T4-H7CDD/Fs) were detected only at trace levels, and no other chlorinated organic compounds were observed. The residue after MC treatment was gray in color, indicating the possibility of carbonization, but the presence of amorphous graphite could not be confirmed.
Nomura
Yugo
Y
Strategic Research Initiative for Survival Paths, Graduate School of Technology, Tokyo University of Agriculture and Technology, 2-24-16 Naka, Koganei, Tokyo 184-8588, Japan. nomura-yuugo@jqa.jp
Nakai
Satoshi
S
Hosomi
Masaaki
M
D001572:Benzofurans / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry; D002713:Chlorine / Q000032:analysis / Q000737:chemistry; D004785:Environmental Pollutants; D008401:Gas Chromatography-Mass Spectrometry; D010087:Oxides / Q000737:chemistry; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000737:chemistry; D013232:Steel; D018505:Waste Management / Q000379:methods*; D014961:X-Ray Diffraction
D001572:Benzofurans; D001713:Biphenyl Compounds; D017610:Calcium Compounds; D004785:Environmental Pollutants; D010087:Oxides; D000072317:Polychlorinated Dibenzodioxins; D013232:Steel; D002713:Chlorine; C008694:octachlorodibenzofuran; C016538:lime; C006983:4-chlorobiphenyl; C018117:octachlorodibenzo-4-dioxin