Electrochemistry of reduced sulfur species in natural waters—I. The H2S-H2O system

Careful measurements of rest potentials of platinum electrodes (Eh) in the H2S-H2O system were made together with measurements of the pH and the potentials of Ag-Ag2S electrodes (Es2−). The potentials of the platinum electrode are characteristic of H2S chemisorption followed by H2S discharge on the platinum. The relations between Eh, Es2− and pH are characteristic of the H2S-H2O system and of the hydrogen sulfide concentration. Thus these parameters can be employed to distinguish H2S-H2O systems from H2S-S8-H2O systems. Field measurements on hot sulfurous springs are in agreement with laboratory data.