The various embodiments of the invention relates to the composition of a hydrogen sulfide capture material and the related method of manufacture. The hydrogen sulfide capture material is formed by solubilizing an iron source in acid to form an aqueous solution comprising iron chloride, neutralizing the aqueous solution with a caustic solution to form a neutralized solution, washing the neutralized solution to separate it into water and a slurry, forming a thickened slurry by removing additional water from the slurry, separating the thickened slurry to produce filtered water and a wet filter cake, and drying the wet filter cake to form granules. The hydrogen sulfide capture material of the present invention removes hydrogen sulfide for a longer time and at a faster rate than the materials of the prior art, thereby improving the efficiency and decreasing the cost of sour gas treatment.