Theoretical Study on Destruction Mechanism of 2,3,7,8-TCDD by O3 and NO3
- Received Date: 2009-11-12
- Ozone, Dioxin, 2,3,7,8-tetrachlorodihenzo-p-dioxin, Quantum chemistry, De-struction mechanism
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.
|Citation:||Zhi-hua Wang, Zheng-cheng Wen, Jiang-rong Xu, Jiang-rong Xu, Ke-fa Cen. Theoretical Study on Destruction Mechanism of 2,3,7,8-TCDD by O3 and NO3[J]. Chinese Journal of Chemical Physics , 2010, 23(3): 303-309. doi: 10.1088/1674-0068/23/03/303-309|