Development of an efficient electrochemical process for removing and separating soluble Pb(II) in aqueous solutions in presence of other heavy metals: Studies of key parameters

Abstract

A very simple electrochemical process was developed for a high efficient elimination of Pb(II) from wastewaters. The principle is to remove soluble Pb(II) as oxide(s) adherent thin films only on the effect of an imposed specific potential by chronoamperometric method and an adequate pH, without adding reagents, at room temperature and in a conventional container. This treatment is very efficient for removing 99.99% of Pb(II) and directly reaching acceptable concentrations for the environment and drinking water standards, with low energy input. Firstly, the key parameters that could influence the efficiency of lead removal, such as the pH and the adequate values of potential, the initial concentration and the duration, were studied in pure water. Systematically, the solution was analyzed to quantify the concentration of Pb(II), and the recovered solid as an adherent thin film was characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) to determine its nature according to the experimental conditions. In a second part, the same treatment was applied with the optimized conditions in the presence of chemical ionic species and other heavy metals such as Cd(II), Ni(II) or Cu(II) to confirm the possibility to have a total elimination and separation of lead from these other heavy metals. To conclude, this electrochemical process was applied with success on an effluent coming from a wastewater treatment plant (WWTP), which confirms the real interest of this easy electrochemical process for an efficient separation and purification of wastewaters containing soluble lead.