Formation Pathways of Mono- to Octa-Chlorinated Dibenzo-p-dioxins and Dibenzofurans in Main Organochemical Industries

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• 作者：Ying Han ; Wenbin Liu ; Wenxiao Pan ; Pu Wang ; Zhenyu Tian ; Yuyang Zhao ; Mengjing Wang ; Xuebin Chen ; Xiao Liao ; Minghui Zheng
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：September 15, 2015
• 年：2015
• 卷：49
• 期：18
• 页码：10945-10950
• 全文大小：408K
• ISSN：1520-5851

文摘

The concentrations and formation pathways of mono- to octa-chlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were investigated in main organochemical industries. High levels of PCDDs and PCDFs were detected. The total concentrations of 27 PCDD/F congeners in chloranil, 2,4-D, and 1,4-dichlorobenzene were 5302397 卤 8944449, 20963 卤 15908, and 242 卤 67 pg g^鈥?, respectively, and the less-chlorinated PCDD/F levels were 12006 卤 20155, 9536 卤 5594, and 195 卤 94 pg g^鈥?, respectively. The distribution trends of less and more chlorinated PCDD/Fs were similar in different chemical plants because of their similar formation pathways, which may also be related to the degree of chlorination of chemical products and purification processes. 1,2,3,4-TeCDF and 2,4,8-TrCDF were selected as model molecules to calculate the bond dissociation energy, showing that 2-MCDF, 3-MCDF, and 2,8-DCDF are more easily formatted as shown by the analytical results. The formation pathways of less to more chlorinated PCDFs are proposed to explain why 2-MoCDF, 2,8-DiCDF, 2,4,8-TrCDF, and 2,3,4,7,8-PeCDF are the dominant congeners and to explain why 2,3,4,7,8-PeCDF is the largest contributor of I-TEQs in most studies.