Electrophilic chlorination of dibenzo-p-dioxin and dibenzofuran over composite copper and iron chlorides and oxides in combustion flue gas. (October 2020)

• Record Type: Journal Article
• Authors: Wang, Dan; Zhang, Haijun; Ren, Meihui; Fan, Yun; Gao, Yuan; Lv, Zhenzhong Yang; Yu, Ying; Chen, Jiping
• Is Part Of: Chemosphere. Volume 256(2020)
• Publication Date: 2020-10
• Subjects: Chlorination -- Fe and Cu chlorides -- Dioxins -- Combustion flue gas; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.127065
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Dibenzo- p -dioxin (DD) and dibenzofuran (DF) chlorination mediated by Cu and Fe chlorides can make a direct contribution to the formation of polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/Fs) in combustion flue gas. In this study, a kind of composite Cu and Fe chlorides and oxides (CuFe9 O9.5 Cl10 ) was prepared by impregnating oxides with HCl solution to imitate the coexistence status of Cu and Fe species in combustion flue gas. Composite CuFe9 O9.5 Cl10 was active in promoting the electrophilic chlorination of DD/DF at 150–300 °C, with the highest activity at 200 °C. DD/DF chlorination could occur under inert atmosphere, and 5% O2 atmosphere was most favorable for DD/DF chlorination. Electrophilic chlorination of DD/DF primarily favored at 2, 3, 7, 8 positions. Hybridization of Cu and Fe chlorides and oxides not only decreased the starting temperature and activation energy of DD/DF chlorination, but also induced a synergistic effect for accelerating the chlorination of DD/DF. The measured activities of composite CuFe9 O9.5 Cl10 for promoting the chlorination of DD/DF were near to those of composite Cu chloride and oxide (CuO0.2 Cl1.6 ), whereas 2 orders of magnitude higher than those of composite Fe chloride and oxide (FeO0.3 Cl2.4 ). Comparison of PCDD/F congener distribution patterns indicated that DD/DF chlorination should be a main source of Cl1−3 DFs and Cl1−2 DDs in combustion flue gases. Graphical abstract: Image 1 Highlights: Composite CuFe9 O9.5 Cl10 was highly active in accelerating the chlorination of DD/DF. Mixed Cu and Fe chlorides induced a synergistic effect for DD/DF chlorination. Electrophilic chlorination of both DD and DF primarily favored at 2, 3, 7, 8 positions. DD/DF chlorination should be a main source of Cl1−3 DFs and Cl1−2 DDs in flue gas. Abstract.