Abstract
The feasibility of catholyte-conditioning to enhance the electrokinetic (EK) remediation of cobalt and lead polluted soil has been
investigated in this study. Electrokinetic experiments were conducted using an EK cell 10 cm in width, 10 cm in height, and 50
cm in length. Plate type electrode of graphite was used as electrode material. Two experiments were conducted under constant
voltage condition (2 V/cm). The pH values of the soil significantly affect the removal of Co and Pb ions. Due to electrolysis
reaction, soil pH increases near the cathode and without pH conditioning, metals precipitate as hydroxides. This problem is
solved by the addition of nitric acid (0.1N) in the catholyte compartment. Significant movement of metals was observed through
the soil with high removal efficiency. Results showed that catholyte conditioning using nitric acid increased the removal of cobalt
and lead from the soil and, consequently, the maximum removal achieved was 73.84% and 62.88% for cobalt and lead,
respectively. These EK tests indicate that the increased experimental time induced a higher removal efficiency of cobalt and lead.
The results suggest that longer treatment periods will result in further transport of cobalt and lead in the sample. Also, it indicated
that the highest quantities of cobalt and lead moved towards the catholyte, particularly at upper 5 cm. On the basis of the
experimental results, we conclude that the electrokinetic remediation, using 0.1N HNO3 as catholyte-conditioning, is suitable for
extracting cobalt and lead from polluted soil.