Investigation into the bromination of polybrominated dibenzo-p-dioxins and dibenzofurans

The formation and emission of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) are under consideration for inclusion in the Stockholm Convention due to their significant environmental and health hazards. This study systematically investigated the aromatic bromination mechanism in municipal solid waste incineration (MSWI) flue gas, with a focus on the catalytic roles of FeBr₃, CuBr₂, Fe₂O₃, and CuO in PBDD/Fs formation. Iron-containing particles exhibited significantly higher activity than copper-based counterparts in promoting bromination, particularly in the synthesis of highly brominated PBDD/Fs. Mechanistic analysis revealed that positions 1/4/6/9 and 2/3/7/8 on aromatic structures are highly susceptible to bromination substitution reactions, with the reactivity influenced by the metal type. Meanwhile, this study showed that the core cycle of the aromatic bromination was the bromination-oxidation-debromination, while those with the copper particles were mainly bromination-debromination reactions. These findings highlight the critical role of iron in pollutant formation and provide a theoretical foundation for controlling PBDD/Fs emissions in MSWI flue gas. Future efforts should extend this work to industrial-scale conditions and explore multi-metal interactions to optimize emission reduction strategies under the Stockholm Convention framework.