Fe–Cu Galvano–Fenton process for simultaneous dye oxidation and electricity generation

This study explores the batch degradation of Methyl Violet 2B (MV2B) in aqueous solution using a Fe–Cu Galvano–Fenton system, which combines galvanic corrosion and Fenton chemistry. The Fe–Cu galvanic cell operates as an electrochemical system capable of simultaneously degrading the dye and generating electricity, with an external circuit enabling electron recovery. Key operational parameters—including pH, electrode distance, immersion time, H₂O₂ concentration, temperature, and initial dye concentration—were optimized. The highest degradation efficiency and power density were achieved at pH ≤ 3 and 55 °C, with an optimal H₂O₂ concentration of 4 mM. Decreasing electrode spacing and increasing immersion time significantly enhanced the system’s performance. The process yielded substantial removal rates: TOC (86.52%), COD (68.62%), BOD (59.42%), suspended solids (76.32%), and turbidity (100%). Additionally, the system generated a peak power density of 140 W/m2. Kinetic analysis revealed a first-order reaction with an activation energy of 39.3 kJ/mol. Thermodynamic evaluation indicated that MV2B degradation is generally non-spontaneous but becomes favorable at elevated temperatures, as confirmed by Gibbs free energy values.