Removal of lead from wastewater consisting of lead nitrate by cementation on a gas-sparged zinc rod was investigated experimentally. Detailed observations were made for the deposited lead by scanning electron microscope (SEM) to show the porosity and nodular structure of the lead deposit. The activation energy for the process was found to be 10 kcal/g.mol. The rate controlling step was found to be diffusion of lead ion through a solution boundary layer surrounding the zinc cylinder. Accordingly, rates of cementation were expressed in terms of the mass transfer coefficient. Variables studied were initial lead ion concentration, length of the zinc cylinder, temperature and N-2 flow rate. Increasing the height of the zinc cylinder was found to decrease the mass transfer coefficient. The experimental data were correlated by the equation: J=0.195+0.55(Fr.Re)(-0.109)(L/d)(-0.5).