Advanced Oxidation of Organic Dyes Using a Porous Gold Electrode: Kinetic Analysis

MAX 250 words This study evaluates the efficiency of anodic oxidation processes for the degradation of the azo dye Reactive Blue 203 (RB203) using a gold electrode in an compartmented electrochemical cell. Unlike most studies that rely on conventional electrodes such as BDD or graphite, this work explores the use of a porous gold electrode—an uncommon yet promising material in dye degradation—highlighting its high electrocatalytic activity and exceptional chemical stability. Experiments explored the effects of current density, initial pH and type of supporting electrolyte. The gold electrode performed remarkably well, achieving a 91.82% decolorization rate and 96% Chemical Oxygen Demand (COD) removal after 360 minutes of treatment. Best performance was observed under acidic conditions (pH = 3), where the formation of hydroxyl radicals (●OH) is favored. The use of KCl as a supporting electrolyte improved degradation compared to Na₂SO₄, thanks to better ionic conductivity and the generation of reactive species such as Cl₂ and HOCl. Kinetic analysis revealed that the reaction follows a pseudo-first-order model, with rate constants increasing from 0.00261 min-¹ to 0.0141 min-¹ as the current density increases from 100 to 400 mA.cm-². These results confirm that anodic oxidation, with the gold electrode, is an effective and sustainable method for treating textile wastewater