Dechlorination/hydrogenation and destruction reactions of PCDDs in OCDD-added fly ash heated under vacuum.
Octachlorodibenzo-p-dioxin (OCDD)-added, pretreated fly ash was heated under vacuum at sample temperatures ranging from T(s)=450 to 650 K. The fly ash and liquid nitrogen-cooled trap samples were analyzed for DD/DF through OCDD/DF. The total amounts of DD through OCDD decrease with increasing T(s), which indicates that dechlorination/hydrogenation (DCH) reactions are not the only reaction channels. Reduction of toxic equivalent (TEQ) for PCDDs by more than 99% was achieved in the fly ash by the vacuum heat treatment at T(s)=650 K for 4 h. The total amount of PCDDs and DD detected in the liquid nitrogen-cooled trap relative to that of added OCDD was about 17%, i.e., PCDDs and DD which were adsorbed to the fly ash surfaces can evaporate into the gaseous phase. The difference between the evaporation behavior of PCDDs in the present and the previous studies is discussed in the light of their states of existence.
Misaka
Youhei
Y
Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
Abe
Tsuyoshi
T
Takeuchi
Kazuhiko
K
Ohba
Kazuo
K
Sawabe
Kyoichi
K
Shobatake
Kosuke
K
D000393:Air Pollutants / Q000032:analysis*; D002244:Carbon / Q000737:chemistry*; D060729:Coal Ash; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D006865:Hydrogenation; D017745:Incineration / Q000592:standards; D008956:Models, Chemical; D052638:Particulate Matter; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis; D014618:Vacuum
D000393:Air Pollutants; D060729:Coal Ash; D052638:Particulate Matter; D000072317:Polychlorinated Dibenzodioxins; D002244:Carbon; C018117:octachlorodibenzo-4-dioxin