Advanced electrochemical degradation of Methyl Orange using a silver-functionalized 3D-printed electrode

In this work, we present a novel three-dimensional electrode (Ag@A3D-E) fabricated via 3D printing using a conductive PLA/carbon black filament, chemically and electrochemically activated, and functionalized with silver nanoparticles (Ag NPs). The developed electrode was applied for the electrochemical degradation of methyl orange (MO), a model azo dye, in a chloride-containing electrolyte. Structural and morphological characterizations confirmed the successful deposition of crystalline Ag NPs and the exposure of conductive carbon networks upon activation. Electrochemical analyses demonstrated a substantial enhancement in conductivity and catalytic activity after modification. Under optimized conditions (2 V, pH 6.5, 0.25 M KCl), the Ag@A3D-E achieved 100 % decolorization within 60 min and 98.1 % COD removal after 4 h, highlighting its excellent degradation and mineralization efficiency. UV-Vis, FT-IR, and COD analyses indicated that degradation proceeds via indirect oxidation, primarily through in situ-generated reactive chlorine species and hydroxyl radicals. The system also exhibited excellent reusability and efficacy in treating multi-dye solutions, demonstrating its potential for scalable and sustainable wastewater treatment.