张梦玫,李晓东,陈彤.氯化铜催化二噁英生成实验及指纹特性分析[J].环境科学学报,2019,39(8):2735-2746
氯化铜催化二噁英生成实验及指纹特性分析
- Copper chloride catalyzed PCDD/F-formation: Experiments and PCDD/F-signatures
- 基金项目：国家重点研发计划战略性国际科技创新合作重点专项（No.2016YFE0202000）
- 张梦玫
- 浙江大学热能工程研究所, 能源清洁利用国家重点试验室, 杭州 310027
- 李晓东
- 浙江大学热能工程研究所, 能源清洁利用国家重点试验室, 杭州 310027
- 陈彤
- 浙江大学热能工程研究所, 能源清洁利用国家重点试验室, 杭州 310027
- 摘要：氯化铜被认为是对二英（PCDD/F）生成促进作用最强的金属催化剂，温度和氧气含量是影响其催化二英生成的关键因素.本文选取250~550℃间8个不同温度点及0~20%间4种不同氧气含量，系统性地研究了温度和氧气含量对含氯化铜模拟飞灰（MFA）生成二英的影响，并通过分析指纹特性探讨二英的生成路径和机理.结果发现，290~350℃之间二英生成量较高，且在290℃时二英总量达到最大值；氧气含量为10%时二英生成量达到最高.研究二英同分异构体分布可从分子层面为研究其生成路径和机理提供重要信息，因此，本文分析了四至八氯代PCDD/F的全部异构体的分布.结果表明，在本文所选取的温度和氧含量范围内，温度对二英生成路径的影响高于氧气含量.最后，重点讨论了2，3，7，8位氯取代的17种有毒异构体的分布随温度和氧气的变化情况及生成路径.利用主成分分析法（PCA）证实了氯化铜催化二英从头合成过程中存在经由氯酚路径生成的异构体，并讨论了不同工况下氯酚路径对二英生成的影响.
- Abstract：Copper chloride (CuCl2) has been identified as the strongest among various catalysts for formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F). This study systematically explores the effect of temperature and oxygen on the formation of PCDD/F from CuCl2-catalyzed system, over a wide range of temperature (250~550℃) and oxygen content (0~20%). Both PCDD/F-output and its signature are extensively characterized, including homologue and isomer profiles. The temperature range between 290 and 350℃ largely promotes the formation of PCDD/F and a maximum output is reached at 290℃. An oxygen content of 10% in the gas phase is favorable for forming PCDD/F. Isomer-specific information is essential for researchers in their quest towards reaction mechanisms. In all cases a complete analysis on isomer distribution pattern is produced. Still, temperature exhibits a more significant influence on isomer profiles than oxygen content ranging from 5% to 20%. Special attention is paid to the seventeen 2,3,7,8-substituted isomers, to their behaviour and relationship. The existence of chlorophenols (CP)-route congeners in CuCl2-catalyzed de novo formation is confirmed by principal component analysis (PCA); their contributions at different conditions are then discussed.
