Removal of lead ions from acidic aqueous solutions by cementation on iron

The kinetics of the cementation of lead from acidic solutions onto rotating iron discs have been studied over a large range of initial lead ion concentrations, disc rotation speeds and temperatures. The cementation is shown to be a first-order reaction which is diffusion-controlled. The activation energy was found to be 9.6 kJ mol −1. The rate of the reaction is affected by the increase in the electrode surface area with increasing cementation time and initial lead ion concentrations. The electrochemical impedance spectroscopy was used to estimate the variation of the surface area during cementation.