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

Abstract

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.