Electrochemical recovery of hydrogen and elemental sulfur from hydrogen sulfide gas by two-cell system

Abstract

ABSTRACT In spite of industries making huge investments, for a viable energy saving, still the methods for conservation of energy are lagging and the industries are still in search for alternatives. The major concern that persists with the oil and gas operations is emission of hydrogen sulfide, frequently or inadvertently, during the initial or later stages of the process. Hence, this study focuses on the indirect electrolysis toward the recovery of sulfur and hydrogen from hydrogen sulfide using graphite as both anode and cathode with calomel as reference electrode. The recovered sulfur was analyzed using high-resolution scanning electron microscope was in range of few microns that was in agreement with the X-ray diffraction analysis confirming the crystalline orthorhombic structure of sulfur (JCPDS Card no.89–2600). The cyclic voltammetry experiment was carried out by sweeping the potential between −1.2 and +1.2 V at a scan rate of 50 mVs−1 obtaining a maximum current density of 0.41 A/cm2. Maximum deposition of sulfur observed at pH 13 with a current density of 0.23 A/cm2 and temperature 80°C. The quantity of sulfur recovered by indirect electrolysis was in the range of 2.9 mg with efficiency of 90.44%.Thus an effective method using indirect electrolysis method was successfully used to achieve crystalline sulfur and hydrogen from H2S.