Treatment of gaseous streams polluted with H2S: Comparison of electrolytic and electro-Fenton assisted absorption processes

• Published in: Chemosphere (Oxford) 2023-05, Vol.323, p.138254-138254, Article 138254
• Main Authors: Girón-Navarro, Rocío, Arias, Andrea N., Linares-Hernández, Ivonne, Martínez-Miranda, Verónica, Teutli-Sequeira, Elia Alejandra, Lobato, Justo, Rodrigo, Manuel A.
• Format: Article
• Language: English
• Subjects: absorbents; absorption; air pollution; atmospheric pressure; Electro-absorption; Electro-Fenton; electrochemistry; electrolytes; Hydrogen peroxide; Hydrogen sulphide; MMO anode; oxidation; phosphates; species; sulfur
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.138254

H2S is a gaseous compound that contributes to air pollution. In this work, the electrochemical oxidation treatment of gaseous streams polluted with H2S is evaluated using a jet mixer and electrochemical cell device, in which the performance of electrolytic and electro-Fenton assisted absorption processes are compared. Results demonstrate the feasibility of both processes to remove H2S, reaching coulombic efficiencies of nearly 100% in the electrolytic assisted absorption, and 70–80% in the electro-Fenton assisted absorption. Aqueous solutions containing phosphate salts as electrolyte were found to be suitable as absorbents for the process. Efficiency in the cathodic production of H2O2 in these solutions using the experimental device was found to be as high as 32.8% (1.184 mgH2O2/min) at 12 °C and atmospheric pressure. Sequential formation of SO2 and SO3 is obtained by the oxidation of H2S contained in the gas. These species are hydrolysed, and a part remained in the absorbent as SO32− and SO42−, while the rest is dragged in the outlet gas. SO3 production is promoted by electrolytic assisted absorption and polysulphides by the electro-Fenton technology. Low concentrations of elemental sulphur are detected in the solid suspensions formed during the process. [Display omitted] •Elimination of H2S from gaseous streams by electrochemically assisted absorption.•Electrochemical production of H2O2 with efficiency as high as 32.8%.•Coulombic efficiency of 100% in electrolytic absorption and 80% in electro-Fenton.•Electrolytic absorption produces mainly SO3 and electro-Fenton, polysulphides.•Applying 0.3 A, removals rates of H2S as high as 1.827 mgS/min are obtained.