二噁英形成机理研究进展

Research Progress on the Formation Mechanism of Dioxin

二噁英是一类高毒性和生物蓄积性的持久性有机污染物(POPs),对环境中二噁英的性质、来源及生成机理进行深入研究,有助于减少其对环境和人体健康的危害。本文对二噁英的基本性质、来源及形成途径进行了综述。二噁英的形成途径主要包括废弃物焚烧、冶金、造纸及含氯化学品制造。二噁英来源不同,形成机理也不同。在废弃物焚烧过程中,二噁英的形成机理主要包括直接释放、高温气相生成、从头合成及前驱物合成。冶金工业二噁英的形成机理主要包括电炉冶炼废钢及铁矿石烧结,产生二噁英的机理类似于废弃物焚烧的从头合成及前驱物合成;造纸工业中,二噁英主要来源于原料带入及含氯漂白剂漂白,其中氯化过程形成的可吸附有机氯是形成二噁英的主要前驱物;含氯化学品制造及氯碱工业也是二噁英的主要来源,其常存于产品、废气、废渣及废水中。研究二噁英生成机理,可以为有效减控二噁英的生成提供思路与方法。

Dioxins are a class of highly toxic and bioaccumulative persistent organic pollutants (POPs),in-depth research on the nature,source and generation mechanism of dioxins in the environment will help reduce their harm to the environment and human health.This paper reviews the basic properties,sources and formation pathways of dioxins.The formation of dioxin mainly includes waste incineration,metallurgy,papermaking and manufacture of chlorine-containing chemicals.Different sources of dioxins have different formation mechanisms.In the process of waste incineration,the formation mechanism of dioxin mainly includes direct release,high temperature gas phase generation,de-novo synthesis and precursor synthesis.The formation mechanism of dioxin in the metallurgical industry mainly includes electric furnace smelting of scrap steel and iron ore sintering,and the mechanism of dioxin production is similar to the de-novo synthesis of waste incineration and the synthesis of precursors;in the paper industry,dioxins mainly come from the introduction of raw materials and the bleaching of chlorine-containing bleaching agents,and the adsorbable organic chlorine formed during the chlorination process is the main precursor for the formation of dioxins;the manufacture of chlorine-containing chemicals and the chlor-alkali industry are also major sources of dioxins,which are often found in products,waste gas,waste residue and wastewater.Studying the generation mechanism of dioxin can provide ideas and methods for effectively reducing and controlling the generation of dioxin.