Influence of electrolyte hydrodynamics on current yield in ferrate(VI) production by anodic iron dissolution

The dependence of current efficiency for ferrate(VI) synthesis on the superimposed electrolyte flow rate was determined using 14 an NaOH solution and a white cast iron electrode. The electrolyte mean velocity in the cell ranged from 0.4 to 2.9 cm s(-1) and current density from 1.4 to 35.3 mA cm(-2). It was found that current efficiency was influenced by electrolyte velocity only at current densities lower than 7 mA cm(-2). This is explained in terms of the removal of intermediate products from the anode surface by the electrolyte convection. This factor becomes negligible at higher current densities in comparison to mass transfer induced by oxygen evolution on the anode surface.