Efficient removal of carbonyl sulfur and hydrogen sulfide from blast furnace gas by one-step catalytic process with modified activated carbon

[Display omitted] •Highly efficient removal of COS and H2S from blast furnace gas by one-step method.•Combined sulfur capacity of 218.21 mg/g, exceeding that of previous studies.•Optimal desulfurization performance obtained at a reaction temperature of 60 °C.•Hydrolysis-oxidation-deactivation mechanism proposed for reaction with Cu-K-Co/AC. The performance of modified activated carbon (AC) and the reaction mechanism for the one-step removal of COS and H2S from blast furnace gas were investigated by improving the catalyst preparation conditions. Optimal performance was achieved when the reaction temperature was 60 °C, the oxygen concentration was 0.1 vol%, and the catalyst was prepared by drying at 110 °C. A combined sulfur capacity of 218.21 mg/g was achieved, and the desulfurization mechanism was revealed through a series of characterization methods. The COS in the inlet gas was captured on the catalyst surface under the action of alkaline sites and was subsequently hydrolyzed to H2S. The generated H2S and the original H2S dissociated within the water film on the catalyst to generate HS- and H+. The lattice oxygen of CuO and Cu2O was activated, and the active oxygen oxidized most of the HS- to elemental S. Meanwhile, some of the HS- combined with metal ions to form sulfides, and CoPcS acted as an auxiliary to facilitate this oxidation process. The elemental S was further oxidized by reacting with H2O to form sulfuric acid, which interacted with the active components to form sulfate. This process eventually led to the deactivation of the catalyst.