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| Theoretical Study on Destruction Mechanism of 2,3,7,8-TCDD by O3 and NO3 |
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Zhi-hua Wang1, Zheng-cheng Wen*2, Jiang-rong Xu3, Jiang-rong Xu1, Ke-fa Cen1
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1.State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China;2.State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China College of Science, Hangzhou Dianzi University, Hangzhou 310018, China;3.College of Science, Hangzhou Dianzi University, Hangzhou 310018, China
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| Abstract: |
| In order to improve the destruction effciency of dioxins and also for developing new dioxin control technology, the destruction mechanisms of 2,3,7,8-tetrachlorodihenzo-p-dioxin (2,3,7,8-TCDD) by O3 and NO3, were investigated employing quantum chemical calcula-tions. For involved reactions, the microcosmic reaction processes were analyzed and de-picted in detail based on geometry optimizations made by the B3LYP/6-31G(d) method. At the same time, the reaction activation energies were also calculated at the MP2/6-311G(d,p)//B3LYP/6-31G(d) level. Configuration analysis indicated that 2,3,7,8-TCDD could be destroyed by O3 and NO3 in two different ways. The destruction of 2,3,7,8-TCDD by O3 proceeded via the addition of O3 and the cleavage of C=C while the destruction of 2,3,7,8-TCDD by NO3 proceeded via the substitution of chlorine by NO3. Calculated re-sults show that, the activation energy of the destruction reaction of 2,3,7,8-TCDD by NO3 (267.48 kJ/mol) is much larger than that of the destruction reaction of 2,3,7,8-TCDD by O3 (51.20 kJ/mol). This indicated that the destruction of 2,3,7,8-TCDD by O3 is much more effcient than that of 2,3,7,8-TCDD by NO3. The reason why the activation energy for the destruction reaction of 2,3,7,8-TCDD by NO3 is so large, is also discussed. |
| Key words: Ozone, Dioxin, 2,3,7,8-tetrachlorodihenzo-p-dioxin, Quantum chemistry, De-struction mechanism |
| FundProject: |
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| Theoretical Study on Destruction Mechanism of 2,3,7,8-TCDD by O3 and NO3 |
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王智化,温正城*,徐江荣,周俊虎,岑可法
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1.浙江大学能源清洁利用国家重点实验室，杭州310027;2.杭州电子科技大学理学院，杭州310018
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| 摘要: |
| 采用B3LYP/6-31G(d)方法优化获得O3及NO3降解2,3,7,8-TCDD反应通道上驻点的几何构型， 得到微观反应进程，并采用MP2/6-311G(d,p)//B3LYP/6-31G(d)方法计算得到相关反应的活化能. 研究表明，O3和NO3采用不同的方式对2,3,7,8-TCDD进行降解. O3通过臭氧加成及碳碳双键断裂使2,3,7,8-TCDD降解，而NO3通过氯取代反应使得2,3,7,8-TCDD上2,3,7,8取代位置上的氯原子被取代为氧原子，从而达到有效降解的目的. O3降解2,3,7,8-TCDD的反应能垒显著小于NO3降解2,3,7,8-TCDD的反应能垒，表明O3降解2,3,7,8-TCDD的能力显著高于NO3. |
| 关键词: 臭氧，二噁英, 2,3,7,8-TCDD, 量子化学，降解机理 |
| DOI：10.1088/1674-0068/23/03/303-309 |
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