All the runs were performed at constant temperature of 25 ◦C. In each run, 250 cm3 of the
wastewater solutions was placed into the electrolytic cell. The current density was adjusted
to a desired value and the coagulation was started. At the end of electrocoagulation, the
solution was filtered and the filtrate was centrifugated at 2000 rpm, and then was analyzed.
Before each run, electrodes were washed with acetone to remove surface grease, and the
impurities on the aluminum or iron electrode surfaces were removed by dipping for 5 min