Removal of Hydrogen Sulfide from Gaseous Streams by a Chemical Method using Ferric Sulfate Solution

Hydrogen sulfide is a toxic and odorous compound present in biogas produced by the anaerobic digestion of biosolids and other organic materials. Reactive absorption of hydrogen sulfide into aqueous ferric sulfate solution is a direct process for H S removal and Sulfur recovery. Apart from sulfur, only H O is 2 2 generated in the process and consequently, no waste treatment facilities are required. A distinct advantage of the process is that the reaction of H S with is so rapid and complete that there remains no danger of discharging 2 toxic waste gas. Effective operation parameters on this process considered. Results show that high temperature and low pressure are suitable for absorption reaction. Variation of hydrogen sulfide concentration and Fe concentration with time in absorption reaction shown that the reaction of ferric sulfate and hydrogen sulfide is first order with respect to the both reactant. At low concentration of Fe (SO ), the absorption rate of H S 2 4 2 increase with increasing the Fe (SO ) concentration. At higher concentration, a decrease in the absorption rate 2 4 3 was found. At higher concentration of Fe (SO ) , the ionic strength and viscosity of solution increase 2 4 3 remarkably resulting in a decrease of solubility, diffusivity and hence absorption rate.