TRANSIENT ANALYSIS OF ANODIC-DISSOLUTION MECHANISM OF IRON IN SULFURIC-ACID-SOLUTION WITH CHANNEL FLOW DOUBLE ELECTRODE

The anodic dissolution mechanism of iron has been investigated using a channel flow double electrode (CFDE) system. The transient current in iron dissolution is separated into partial currents for dissolution of ions and formation of the adsorbed species, using FFT analysis with a dynamic collection number N(omega) of the electrode system. The dissolution of ferrous ions follows the formation of the adsorbed intermediate in the active dissolution potential region. The experimental results support that the anodic dissolution mechanism of iorn in sulfuric acid solution contains two adsorbed species. In the frequency domain, the efficiencies of the formation of adsorbed intermediate on the iron surface PHI(f)(omega) and of the dissolution of ferrous ions PHI(diss)(omega) are obtained from FFT analysis of current transient curves. The amplitude of PHI(diss)(omega) decreases and that of PHI(f)(omega) increases with the frequency. The numerical simulations for iron dissolution based on the reaction model involving two adsorbed species have been performed and the results have agreed well with that of the experiment in time and frequency domains.