Hydrogen sulfide (H2S) is considered as one of the deleterious agents in the feedstock of reformers. In Midrex plants, beside H2S present in natural gas, a nearly high amount of H2S is introduced would be added into the process gas after contacting with iron ores, therefore it is highly essential to remove this content. This material can adversely affect the efficiency of catalysts loaded into the reactors and reduce the catalytic activity of the catalysts during the operation since it is easily adsorbed by nickel metal and occupies the catalyst active sites. 
Zinc oxide adsorbent proved to be the most effective and economic material for sulfur compounds removal and H2S in particular.
 

ZnO (s) + H2S (g) → ZnS (s) + H2O (g)