Removal of Cadmium from Aqueous Environments by Electrocoagulation process using Aluminum Electrodes

Background: The purpose of this study was the evaluation of cadmium removal from industrial
wastewater by electro coagulation process using aluminum electrodes.
Methods and Materials: For this study a glass tank with 1.87 liter volume containing four plate
aluminum electrodes was used to do experiments. The electrodes were connected to the positive and
negative poles of DC power supply (bipolar mode). The tank was filled with synthetic wastewater
containing cadmium ion in concentration of 5, 50 and 500 mg/l and then it was started up. The
amount of cadmium ion removal was measured at pH 3, 7 and 10 and in electric potential range of
20, 30 and 40 volts.
Results: The results obtained at different electrical potentials showed that initial concentration
of cadmium can affect on efficiency removal; moreover, for higher concentration of cadmium,
higher electrical potential or more reaction time is needed. On the other hand, if the initial
concentration increased, the time required of process had to increase too. The final pH was always
higher than initial pH. As expected, the results showed that in a given time, the removal efficiency
increased significantly with the increase for the current density. The highest electrical potential (40
v) produced the quickest treatment with >99% cadmium reduction occurring after only 20 min.
Conclusions: The results showed that, in this process, the use of different electrical potentials
can provide a wide range of pH for doing this process. The method was found to be highly efficient
and relatively fast compared to conventional existing techniques and, it can also be concluded that
the EC process has the potential to be utilized for the cost-effective removal of heavy metals from
water and wastewater.