Iranian Association of Environmental Health (IAEH)
Abstract
The object of this study is the evaluation of cadmium removal from
industrial wastewater by electrocoagulation process. For this study a
glass tank in 1.56 L volume with four plate electrode was used to do
experiments. The electrodes made of iron and connect to the positive
and negative pole of DC power supply (bipolar mode). The tank was
filled with synthetic wastewater that was containing cadmium ion in
concentration 5, 50 and 500 mg/L and then it was started up. The
percent of cadmium ion removal was measured at pH 3, 7 and 10 and in
electric potential range of 20, 30 and 40 volts. At the end of each
stage of experiment, volume of produced sludge was measured. The
results obtained at different electrical potential showed that initial
concentration of cadmium can effect on efficiency removal and for
higher concentration of cadmium, higher electrical potential or more
reaction time is needed. On the other hand, if the initial
concentration increases, the time required of process should increase
too. The final pH for iron electrodes was always higher than initial
pH. As expected, the results showed that for a given time, the removal
efficiency increased significantly with increase of current density.
The highest electrical potential (40V) produced the quickest treatment
with >99% cadmium reduction occurring after only 20 min. The result
showed that, in this process, the use of different electrical
potentials can provide a wide range of pH for doing this process and
electrocoagulation process (using iron electrodes) is a reliable,
safety, efficient and cost-effective method for removal of cadmium from
industrial effluents, especially designed for pH =10 and voltage = 40V
