Thermodynamics and Stoichiometry of Reactions between Hydrogen Sulfide and Concentrated Sulfuric Acid

Abstract A thermodynamic analysis of the possible reactions between hydrogen sulfide and concentrated sulfuric acid shows that four reactions are feasible. However, only two of these reactions apparently occur in experiments at 1 atm and 0°C to 150°C. Hydrogen sulfide is first oxidized by molecular sulfuric acid, forming SO 2 , sulfur and water, and then the H 2 S may react with the dissolved product, SO 2 , to generate sulfur and water. The stoichiometry of the consecutive reactions and their dependence on acid concentration were determined experimentally using mass balance measurements. The results of this study suggest a possible alternative method for sulfur removal and recovery that has more advantages.