Insight into the Transformation Behaviors of Dioxins from SinteringFlue Gas in the Cyclic Thermal Regeneration by the V2O5/ACCatalyst-sorbent

Dioxins in the sinteringflue gas are usually removed through integrated elimination technologies by carbonaceouscatalysts. However, the regeneration of the used catalyst is poorly investigated, leading to the risk of leakage of dioxins. Herein, theinfluences of cyclic regenerations on the dioxin removal performance of a catalyst (V2O5/AC) were investigated systematically withdibenzofuran (DBF) as a model pollutant. It was demonstrated that the adsorption capacity and oxidation activity of catalystssignificantly declined after several regeneration cycles due to the decreasing external specific surface area and V5+, respectively.Compared with 79.12% DBF directly emitted from a regenerator during N2regeneration, the emission of DBF was only 29.93% withthe modification of the regeneration process through O2addition and temperature adjustment. The possible regenerated productswere also analyzed to disclose the transformation behaviors of DBF. The regeneration mechanisms of DBF followed thetransformation pathway of dibenzofuranol, benzofuran, anhydride species, and ultimately to CO2and H2O. Moreover, theaccumulated heavy aromatics on the surface could be decomposed by introducing O2. This research provides a comprehensiveunderstanding of dioxin transformation behavior and a theoretical basis for efficient control of dioxin removal in the whole integratedremoval technologies.