Fig. 1 – Influence of the Fe2D concentration on COD evolution during the electrolysis of alizarin red. Conditions: Na2SO4 0.05 M, pH[3; T[25 8C; I[200 mA; Fe2D concentration: (,) 0mM; (O) 0.25 mM; (B) 0.5 mM; (>) 1.0 mM; (3) 2.0 mM. The inset shows the evolution of COD removal after 4 h of treatment as a function of Fe2D concentration.