A cylindrical electrocoagulation cell of 250 mL internal volume (V)
was equipped with two parallel plates of rectangular shape
(4.7 cm× 4.7 cm× 0.1 cm; electrode gap e= 1.5 cm), used as anode
and cathode, respectively. Either iron or aluminium electrodes could
be used in order to compare the influence of electrode metal.
Experiments were carried out at room temperature (20± 1 °C).
Before each run, both electrodes were cleaned, immersed in 0.01 M
HCl for 2 min and, amply rinsed with water, air-dried and weighted
before use. During EC, a DC power supply (BK-Precision, USA) was
used in the intensiostat mode; cell voltage (U) was measured. Current
(I) was varied in order to achieve current density values (j) between
7.5 and 65 mA/cm2
. Magnetic stirring at 300 rpm maintained
moderate mixing during EC near the electrodes, while preventing
the destruction of the flocs during their formation. Electrolysis time
(t) was varied between 2 and 10 min. Then, flotation and settling