飞灰特性及氯对二噁英从头合成机理的影响

氯源是二噁英生成的关键因素之一，该文在管式炉中研究了飞灰中的氯形态以及物理化学特性对从头合成二噁英的影响，利用高分辨色谱/低分辨质谱(HRGC/LRMS)测定了气相以及固体残渣中的二噁英，试验结果表明，飞灰中的无机氯含量高于有机氯含量，而有机氯中，可以提取有机氯含量高于不可提取有机氯含量，飞灰中的不可提取有机氯是最能促进二噁英生成的氯源。采样主成分分析法得到的结果为二噁英及其毒性当量与飞灰的比表面积以及氯含量之间正相关，与pH值之间负相关，与飞灰中的金属元素铁、锌之间也有一定的负相关关系，而与碳、铜的关联则不大。

Effects of Chlorine Speciation and Characteristic of Fly Ash on the De Novo Formation of Polychlorinated Dibenzo-P-Dioxins and Dibenzofurans

Chlorine is one of the key parameters for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) formation. The effects of chlorine speciation and physical chemistry characteristic of fly ash on the de novo formation of PCDD/Fs were studied in a tubular oven. The PCDD/Fs in gas and solid phase were detected by high resolution gas chromatograph/low resolution mass spectrometer (HRGC/LRMS). The experimental results show that, the inorganic chlorine content is higher than that of organic chlorine and the extractable organic chlorine content also higher than that of nonextratable organic chlorine. The nonextractable organic chlorine (OCl) in fly ash is the most important chlorine source for de novo formation of PCDD/Fs. From the results of principal component analysis (PCA), levels of PCDD/Fs and international-toxic equivalent quantity (I-TEQ) show a positive correlation with surface area and chlorine content. Negative correlation between PCDD/Fs levels and pH values is also observed. There is also definite correlation between PCDD/Fs levels and iron, zinc amounts in fly ash. However, carbon and copper do not have a noticeable relation with PCDD/Fs levels in fly ash.