Multi-dye decolorization through electrocoagulation treatment utilizing iron electrode (IMS) from iron metal sludge

This research investigates the application of an iron-metal-sludge (IMS) electrode, sourced from industrial waste, in the electrocoagulation process for treating dye-contaminated water. The performance of the electrode was assessed for the removal of Methylene Blue (MB), Acid Blue 29 (AB29), and Reactive Black 5 (RB5) under varying conditions, such as initial pH, current density, and dye concentration. The characterization conducted through SEM-EDX, FTIR, and N₂-sorption demonstrated a uniform distribution of iron and fluoride derived from the PTFE binder, which improved redox activity and electrochemical performance. Cyclic voltammetry (CV) analysis revealed significant redox properties, whereas electrochemical impedance spectroscopy (PEIS) showed minimal charge transfer resistance, facilitating efficient electron flow. The IMS-30PTFE electrode attained approximately 100 % decolorization of all dyes in 60 min under optimal conditions (4 mA/cm², pH 6). Following three reuse cycles, the dye removal efficiency decreased to 55.7 % for RB5, 26 % for AB29, and 10 % for MB, primarily attributed to surface passivation. Metal leaching was minimal, ranging from 0.006 to 0.001 mg/L, and remained within regulatory limits. IMS-30PTFE demonstrates superior electrochemical efficiency, stability, and sustainability as an electrocoagulation electrode for the treatment of dye wastewater. • IMS-30PTFE showed uniform Fe and PTFE distribution, boosting redox activity and charge transfer. • Complete (100 %) RB5 and AB29 dye removal was achieved in 3 h, sustained over 3 operational cycles. • IMS-30PTFE showed strong electrochemical stability with minimal leaching within safe limits. • PTFE integration enhanced electrode durability, ensuring longer lifespan and consistent performance. • Using iron sludge as precursor enables sustainable electrode fabrication from industrial waste.