Enhanced removal of COS from blast furnace gas via catalytic hydrolysis over Al2O3-based catalysts: Insight into the role of alkali metal hydroxide.

• Alkali metal hydroxide can enhance the adsorption capacity of COS. • Compared with LiOH and NaOH, Al 2 O 3 modified with KOH exhibits better performance. • Less by-products were formed on Al 2 O 3 modified with KOH. • The role of alkali metal hydroxide in COS hydrolysis is explored. As blast furnace gas (BFG) can cause air pollution, it is an effective route to convert BFG into a kind of energy. However, it is important to remove carbonyl sulfide (COS) from BFG before burning it. This can be done with catalytic hydrolysis which is considered as a high-efficient technology. In this work, a series of catalysts are prepared via impregnation method to remove COS, in which aluminum oxide (Al 2 O 3) and alkali metal hydroxide (MOH, M = Li, Na and K) are used as base and active component, respectively. Compared with other prepared catalysts, Al 2 O 3 modified with 10% KOH has better catalytic performance in removing COS. The characterization results imply that alkali metal plays a significant role in the enhancement of COS removal efficiency. The capacity of catalysts to adsorb COS is significantly improved with the modification of alkali metal. Moreover, few carbonate or bicarbonate species can be found on the surface of the catalyst during COS hydrolysis. Furthermore, the catalytic mechanism and degradation route of COS hydrolysis on Al 2 O 3 modified with 10% KOH are explored. [ABSTRACT FROM AUTHOR]