Pseudo-boehmite and activated carbon as composite carrier impregnated with K2CO3 for low-temperature simultaneous removal of COS and its hydrolysis product H2S.

The hydrolysis of carbonyl sulfide (COS) by γ-Al₂O₃ has been fully studied, and the removal of hydrogen sulfide (H₂S) by activated carbon (AC) is also an efficient material. Pseudo-boehmite can be used as a binder for molding with AC and as a raw material for preparing γ-Al₂O₃. In this work, a composite carrier was synthesized by combining AC and pseudo-boehmite, and subsequently impregnated with K₂CO₃ using an equal-volume method to produce an effective desulfurizer for the simultaneous removal of COS and H₂S from its hydrolysate at low temperature. When the mass ratio of AC to pseudo-boehmite was 1:3, and 20wt% K₂CO₃ was impregnated, the desulfurizer had the best desulfurization performance. Desulfurization experiments conducted at 70℃ demonstrated the material's capability for simultaneous removal of COS and H₂S. The desulfurizer achieved a maximum COS penetrating sulfur capacity of 130.3 mg/g, while maintaining over 90% removal efficiency for H₂S produced during COS hydrolysis. Characterization by XRD, BET, and FT-IR revealed that the microporous structure contributed primarily by activated carbon facilitated H₂S removal, while mesopores from pseudo-boehmite enhanced COS hydrolysis. The alkaline activation centers provided by K₂CO₃ proved crucial for effective COS hydrolysis. The addition of AC in the desulfurizer not only contributed to the hydrolysis of COS, but also played a decisive role in the removal of H₂S. Additionally, a mechanism for the simultaneous removal of both sulfur compounds was proposed based on the analysis of by-products generated after desulfurization.