Pb2+ ions mobility perturbation by iron particles during electrokinetic remediation of contaminated soil

•Experiments were conducted by use of graphite and iron electrodes.•Effect of citric acid as enhancing agent was also observed.•First 30 h are important for current density variation.•Soil solution monitoring gives valuable information in Pb2+ mobility.

Electrokinetic (EK) remediation is one of the most useful approaches for de-contamination of soils. However, it is unclear that how and when the electrokinetic remediation gives advantages over other remediation techniques in soil. This study was designed to find the influence of Fe2+ particles on the mobility of Pb2+ ions, during electrokinetic remediation, in soil contaminated purposely by lead nitrate Pb(NO3)2. Two types of electrokinetic experiments were performed, by using iron and graphite electrodes. The Fe2+ ions from the iron electrodes, produced due to acidic environment in anode compartment, affected the mobility of lead particles by precipitating as Fe(OH)2. Fe2+ ions enhance the adsorption of lead ions in soil. The results show Fe2+ ions of lower ionic conductivity decreased mobility of other particles in soil. Electrokinetic remediation for up to 120 h with iron electrodes is shown to be less effective for removal of lead. In contrast, graphite electrodes were 15 times more effective in lead removal from soil.