Preparation and characterisation of a new stainless steel/Bi2O3 anode and its dyes degradation ability.

Stainless steel/Bi₂O₃ anode was synthesised by electrodeposition from acidic Bi (III) solution on stainless steel substrate and calcination at 500°C. Characterisation by SEM, EDX, XRD and TGA revealed that the anode surface was fully covered with pure α-Bi₂O₃, which formed a inhomogeneous and porous coat. Three dyes with different chromophores, namely: Reactive Blue 19, Methylene blue and Reactive Orange 4 were completely decolourised by electrochemical oxidation at the synthesised anode in the presence of hydrogen peroxide. Decolourisation followed the pseudo-first order kinetics model for all the three dyes. Decolourisation rates are sorted in descending order: Reactive Orange 4 > Reactive Blue 19 > Methylene Blue. For all the three dyes, an increase of the initial dye concentration caused the decrease of the reaction rate constants. At higher initial dye concentrations, the decolourisation times were significantly prolonged for all the three dyes, however, the complete decolourisation was done as well. [ABSTRACT FROM AUTHOR]