Before run iron electrodes were pickled in 10% HCl for 15 min to remove any rust. The batch experiments were carried out by placing 2 l of freshly prepared chromium salt solution of known initial concentration in the cell. Current was adjusted to a certain value and the corresponding voltage was recorded. Electrocoagulation kinetics was followed by withdrawing a 5 milliliters (mls) sample from the cell every 5 min from the same location. The sample was analyzed using atomic absorption to determine the chromium ion concentration.
In case of Cr3+, 2% NH4Cl was added to avoid interactions of Fe2+ ions with Cr3+. The pH of initial solution was adjusted either by addition of conc. H2SO4 or 30% NaOH