THE INFLUENCE OF ACETATE CONCENTRATION ON THE DISSOLUTION OF IRON IN AQUEOUS-SOLUTIONS

The influence of sodium acetate concentration in the range of 0.1-1.0 M, on the dissolution process of iron in aqueous solution with pH values between 5 and 7, has been investigated. Cyclic voltammetry using rotating disc and ring-disc electrodes was employed. The voltammograms present two anodic peaks and in the first one (more negative potentials) the reaction order with respect to acetate was 0.1 and at the second one a value of 0.3 was found at pH = 5. With respect to the influence of pH, an order of reaction of 0.2 was found in relation to OH- ions, both for the first and the second peak. Kinetic parameters were determined under non-stationary conditions and compared with those found in the literature. It was observed that the passivation is easier to achieve with the increase of acetate concentration or pH.