Evaluation of PCDD/Fs emissions during ceramic production: a laboratory study.
Because of the ubiquity of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in kaolinitic clays, the ceramic industry is considered to be a potential source of PCDD/Fs. However, studies on the emission of PCDD/Fs from ceramic production are still very scarce. In this study, PCDD/Fs emissions during ceramic production were investigated in an electric laboratory batch kiln. The results showed that the PCDD/Fs were completely removed from the ceramic pieces after 30 min of firing at the peak temperature of 1200°C. Nevertheless, on the mass and international toxic equivalent basis, 27.5% and 46.2% of the total PCDD/Fs amount in the raw clay were released into the atmosphere during firing, respectively. These PCDD/Fs were emitted into the air before the temperature was elevated to a level high enough for their destruction. Dechlorination reactions generated a broad distribution within the PCDD/Fs congeners including a variety of non-2,3,7,8-substituted ones. The emission of PCDD/Fs was decreased to 16.3 wt.% of the total PCDD/Fs amount in the raw clay, when the initial kiln temperature was enhanced to 600°C. The emission of PCDD/Fs could be reduced significantly in the presence of a glaze coating on the ceramic test piece. These results indicated that ceramic production is an un-neglectable source of PCDD/Fs in the environment.
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China.
Mang
M
Lu
Yi-Jing
YJ
Luo
Zhong-Zhi
ZZ
Zhang
Meng
M
Xiao
Min
M
Zhang
D000393:Air Pollutants / Q000032:analysis*; D001572:Benzofurans / Q000032:analysis*; D002516:Ceramics; D000072338:Dibenzofurans, Polychlorinated; D004784:Environmental Monitoring; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis
D000393:Air Pollutants; D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D000072317:Polychlorinated Dibenzodioxins