Electrochemical removal of hydrogen sulfide from polluted brines using porous flow through electrodes

Abstract

Carbon felt was used in porous electrodes to achieve electrochemical oxidation of sulfide ions from flowing chloride brines. Using X-ray photoelectron spectroscopy (XPS) and Energy Dispersive Spectroscopy (EDS) sulfur was identified as the final reaction product under various potentials and temperatures. While some of the resulting sulfur flows out with the electrolyte the rest remains adsorbed on the graphite surface. The rate of the process and the removal efficiency increase with potential temperature flow rate and sulfide concentration. The measured limiting currents are substantially lower than those predicted from mass transfer correlations. This was attributed to the passivating effects of the sulfur deposited on the internal surface of the porous electrode. Potentiostatic current transients show that the carbon felt electrodes have higher capacity for removing sulfide ions than planar electrodes which is attributed to the large internal surface area of the carbon felt. © Springer 2005.