Activated-carbon-induced morphological and crystal transformation of α-FeOOH for efficient catalytic removal of hydrogen sulfide from blast furnace gas

The performance of FeOOH for the removal of hydrogen sulfide (H2S) has been widely investigated. However, the harsh conditions of use and the difficulty of regeneration limit its practical application. In this study, FeOOH was loaded on activated carbon (AC) by a hydrothermal method to obtain a series of XF-AC catalysts for the removal of H2S from blast furnace gas (BFG). Among these catalysts, 3F-AC exhibited a high penetrating sulfur capacity of 482.3 mg/g and good regeneration performance. It is noteworthy that the use of AC as the support induced the transformation of alpha-FeOOH crystals into amorphous FeOOH and affected their morphology, and uniformly dispersed nanoparticles rather than agglomerated acicular crystals appeared on the surface of AC. The presence of amorphous FeOOH modulated the basic sites and surface hydroxyl groups of the catalysts while generating hydroxyl radicals during the reaction, thus improving the adsorption and oxidation of H2S. More importantly, the structural properties (surface area and pore volume) of 3F-AC enhanced the storage capacity of elemental sulfur and reduced the formation of by-products. The cyclic catalytic role of Fe3+/Fe2+ played an important role in the oxidation process. This work provides a simple and effective strategy for the design of BFG desulfurization catalysts.