Hydrogen sulfide and its precursors can be selectively sorbed from gas streams containing the same by contacting the gas stream at elevated temperatures with a regenerable sorbent comprising a steam-treated support composited with a rare earth metal component. Presteaming the support lowers the amount of rare earth metal component needed to achieve a given activity level for hydrogen sulfide removal. Subsequent to sorption, the sorbent composite may be desorbed and regenerated by treatment with steam (desorption) and an oxidizing gas (regeneration). The sorbent capacity may be increased by the use of alkali or alkaline earth metal components as promoters. A preferred sorbent comprises lanthanum composited with presteamed alumina.