Unravelling the impacts of sulfur dioxide on dioxin catalytic decomposition on V2O5/AC catalysts

Dioxins are high chlorine, toxic, and persistent organic pollutants that exert significant pressure on both human and the environment. From the analysis of current pollutant removal of the whole life cycle, such as integrated removal of NOx, SO 2 and dioxins in a system, the dioxins oxidation activity as well as the distribution of oxidation products in the presence of SO 2 are still a challenge. In this study, dibenzofuran (DBF) was regarded as a model dioxin compound, and V 2 O 5 /AC was used as a catalyst to investigate the impact of SO 2 on degradation activity and the degradation path of DBF. Various characterization results showed that SO 2 could promote the transformation of DBF to intermediates through a reaction with lattice oxygen and lower the apparent activated energy of DBF catalytic oxidation on V 2 O 5 /AC catalysts. The density functional theory (DFT) calculations confirmed that SO 2 improved the oxidation ability of lattice oxygen on V 2 O 5 /AC. The ethyl hydrogen fumarate intermediate decreased and the small-molecule byproducts increased, providing further evidence that SO 2 accelerates the degradation of DBF and its intermediates. However, the formation of VOSO 4 would inevitably deteriorate the adsorption and oxidation abilities of V 2 O 5 /AC. A model is pioneered to describe the relationship between SO 2 promotion and VOSO 4 inhibition on DBF catalytic oxidation on a V 2 O 5 /AC catalyst. This study is expected to provide theoretical guidance for the collaborative abatement of multi-pollutants in flue gas .