Electrochemical Sulphide Oxidation - An Experimental Study

Abstract

Hydrogen sulphide (H2S) is a problem that occurs everywhere in the industries. This has hazardous properties like high corrosive, hazardous when inhaling and high flammability. The gas is either produced naturally or as a by-product in the oil and gas industries.

Electrochemical oxidation was used for the electrochemical treatment of the hydrogen sulphide. This is a technique that requires small amount of energy to oxidise the pollutant. Hydrogen were oxidised to elemental sulphur and then to sulphate. The experiment was tested with different concentrations (300 ppm and 500 ppm) and different potentials (0.0 V, 0.3 V, 0.5 V and 0.7 V). The sulphide removal rate decreased as the potentials were increased and the current productions for the experiment increased in the beginning and started to stabilise towards the end of every experiment.

The oxidation process was studied and analysed using cyclic voltammetry as an electrochemical test. This technique demonstrates when the oxidation and the reduction of the species occurs. The anodic peaks for 300 ppm were Eox_1= + 0.33 V, Eox_2= + 0.67 V and Eox_3= + 0.95 V for the first cycle. The second and the third cycle were similar. In comparison to 500 ppm, one anodic peak was observed at Eox_1= + 0.70 V. The other cycles barely had any anodic peak but the cathodic peak for 300 ppm and 500 ppm were Ered= - 1.5 V.

PBS was another test taken beside cyclic voltammetry to compare and study if any extra oxidation would happen or not. Both 300 ppm and 500 ppm had a tiny anodic peak at + 0.78 V for 300 ppm and + 0.22 V for 500 ppm.