Effect of Zn, Cd compounds on formation of dioxins in model fly ash

doi:10.11949/j.issn.0438-1157.20150034

Abstract

Abstract:

Catalyst is the key factor for formation of dioxins i.e. PCDD/Fs, for which there is not enough study currently. In this paper, the effect of different metal catalyst contained in model fly ash (MFA) on both PCDD/Fs concentration and distribution is studied under laboratory conditions. The results show that ZnO can inhibit the formation of PCDD/Fs. The catalytic effect of ZnCl₂ on PCDD/Fs is far more obvious than that of CdCl₂ and the concentrations of PCDD/Fs obtained are 341.78 and 16.32 ng·g^-1, respectively. PCDD/Fs formed by ZnCl₂ promotion is 338 times as many as that of ZnO, while the concentration of PCDD/Fs catalyzed by CdCl₂ is twice more than that of CdO. Principal component analysis (PCA) is used to research the effect of catalyst on PCDD/Fs distribution. It is observed that the change of distribution for 17 toxic PCDD/Fs catalyzed by different metal catalyst is significant. Meanwhile, the PCDD/Fs concentration rises with increase of O₂ content, but for PCDD/Fs distribution it has only limit influence.

Key words: MFA, metallic compound, PCDD/Fs, de novo synthesis, catalytic effect

摘要：

催化剂是二噁英(PCDD/Fs)从头合成的关键因素,但已有研究仍不足。在实验室条件下利用模拟飞灰(MFA)研究不同金属催化剂对PCDD/Fs生成量及分布的影响。结果表明,ZnO抑制PCDD/Fs的生成,ZnCl₂对PCDD/Fs生成催化作用远大于CdCl₂,生成PCDD/Fs浓度分别为431.78、6.32 ng·g^-1。ZnCl₂催化下生成PCDD/Fs浓度是ZnO的338倍,CdCl₂催化下生成PCDD/Fs浓度是CdO的3倍。Zn、Cd化合物催化下生成PCDD/Fs氯化程度低。利用主成分分析(PCA)研究催化剂对PCDD/Fs分布的影响,结果表明不同金属催化剂作用下,17种有毒PCDD/Fs分布变化显著。同时ZnCl₂催化下,反应气氛中氧含量的提高导致PCDD/Fs生成量增加,但是对PCDD/Fs分布的影响有限。

关键词: 模拟飞灰, 金属化合物, 二噁英, 从头合成, 催化效果

CLC Number:

TK229

LIAO Junhong, YANG Jie, MENG Weijie, LI Xiaodong, CHEN Tong. Effect of Zn, Cd compounds on formation of dioxins in model fly ash[J]. CIESC Journal, 2015, 66(7): 2643-2648.

廖钧红, 杨杰, 孟炜杰, 李晓东, 陈彤. Zn、Cd 化合物对模拟飞灰中二噁英生成的影响[J]. 化工学报, 2015, 66(7): 2643-2648.

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