Sampling and analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDD/Fs） are both time-consuming and expensive. In principle, real-time monitoring of chlorobenzene （CBz） as an indicator for PCDD/Fs could be useful to control and optimize incinerator operating conditions. To test this strategy, CBz was analyzed together with PCDD/Fs in flue gas samples collected from a hospital waste incinerator. Moreover, lab experiments were conducted to investigate the effect of temperature and oxygen on CBz formation from fly ash from the same incinerator. The experimental results demonstrate that chlorobenzene （in particular PeCBz） correlate well with PCDD/Fs, in line with previous research. The optimum temperature of CBz formation is in a range of 350 to 400℃ and CBz yield increases significantly with oxygen, in line with PCDD/Fs formation. This study is useful for confirming the de novo mechanism and defining correlations between CBz and PCDD/Fs.
Mi Yan,Xiaodong LiTong Chen,Shengyong Lu,Jianhua Yan,Kefa Cen State Key Laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou 310027,China
The mechanochemical treatment of fly ash generated from a medical waste incinerator was subjected to grinding for 2 hr at 400 r/min in a planetary ball mill. The treated fly ash was characterized by a suite of analytical methods including High Resolution Gas Chromatograph/High Resolution Mass Spectrometer, Mastersizer 2000 Particle Size Analyzer, QUADRASORBTM SI Surface Area Analyzer, Scanning Electron Microscopy and X-ray diffraction. Results showed that abatement efficiency of polychlorinated dibenzo- p-dioxins and polychlorinated dibenzofurans （PCDDs/Fs） in terms of total concentration averagely amount to 76% which was relatively higher than that of I-TEQ concentration averagely amount to 56%; the most concentration of toxic congeners as well as isomers of PCDDs/Fs decreased after mechanochemical treatment. The treated fly ash was characterized by a more homogeneous distribution of concaves as well as the significant decreasing in overall particle size and great enlargement in surface area. The major crystallization phases or intensities were considerably changed by mechanochemical treatment, of which a new phase containing chlorine formed may be a possible factor suggesting chlorination reaction occurring on the crystalline surface.
Zheng PengQiong DingYangzhao SunChen JiangXinhua GaoJianhua Yan
