Electrochemical behaviour of iron and copper in a culture solution for Spirulina platensis

Cyclic voltammograms of iron and copper electrodes were run in sodium hydro xide, carbonate-bicarbonate buffer and culture media for Spirulina platensi s at 30 degrees C. Potentiostatic steady state polarisation curves for both electrode surfaces in these electrolytes were performed in the presence an d the absence of S. platensis at fixed temperature. Corrosion potential and corrosion current density values of iron and copper were obtained graphica lly from these curves. In all cases, the largest corrosion current density corresponded to the maximum biogenerated-oxygen concentrations, that is, il luminated culture media containing S. platensis. Corrosion potentials of ir on electrodes shifted to positive values for increasing corrosion rates, wh ereas constant corrosion potentials were obtained for copper electrodes ind ependently of the electrolyte.