多氯联苯污染土壤热脱附研究综述
Overview on Thermal Desorption of PCBs-contaminated Soil
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摘要: 综述了近年来国内外热脱附技术在修复多氯联苯(polychlorinated biphenyls,PCBs)污染土壤方面的研究进展。温度和停留时间是影响其脱附效率的最主要因素，另外脱附效果还受土壤性质以及载气、压力等其他因素的影响。氧气存在的条件下，脱附过程中会有呋喃(polychlorinated dibenzofurans,PCDFs)生成，导致整体毒性当量增加。PCBs的物理蒸发是其主要的脱附机制，同时伴随着脱氯和降解。协同热脱附通过添加改性剂，有效促进了PCBs的去除以及降解。冷凝，除尘，吸附一系列尾气处理用来降低尾气中PCBs的含量。文章最后给出了当前国内外的应用情况以及存在问题和今后的发展方向。Abstract: The technology of thermal desorption for remediation of PCBs (polychlorinated biphenyls) contaminated soil was reviewed. The effect of temperature and retention time was the main factor on the removal efficiency of thermal desorption, which was also influenced by soil texture, carrier gas and pressure. In the presence of oxygen, much of PCDFs (polychlorinated dibenzofurans) formation led to the increase of TEQ (toxic equivalency quantity). During thermal desorption, the main mechanism of PCBs removal was physical evaporation, accompanied by dechlorination and decomposition. The synergetic thermal desorption effectively promoted the PCBs removal and destruction by additives addition. Condensation, dedusting and adsorption were used to decrease the PCBs concentration in gas phase. Finally, the application situations of thermal desorption at both home and abroad, as well as problems and prospects were presented in this paper.
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Key words:
- PCBs /
- thermal desorption /
- soil remediation /
- physical evaporation /
- TEQ
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