2.11 Measurement of corrosion potential and corrosion current of an Fe0 electrode
Electrochemical analyses were conducted at 25ºC in an electrochemical cell (8 ml in capacity) equipped with three electrodes, as described by Okamoto et al. (2014), with slight modifications. The working electrode was an Fe0 foil with a surface area of 3.14 cm2, which was placed on the bottom of the electrochemical cell, while the counter and reference electrodes were a platinum wire and an Ag/AgCl/(saturated KCl) electrode, respectively. Filter-sterilized corrosion-test medium was used as an electrolyte into which a cell suspension was injected to a final optical density at 660 nm of 0.02 to start the measurement. The corrosion potential of the working electrode was measured continuously, except that, every 8 h, the corrosion potential of the working electrode was swept at ±25 mV versus the corrosion potential for the measurement of the corrosion current of the working electrode.