REMOVAL OF CADMIUM FROM INDUSTRIAL EFFLUENTS BY ELECTROCOAGULATION PROCESS USING IRON ELECTRODES

The object of this study is the evaluation of cadmium removal from industrial wastewater byelectrocoagulation process. for this study a glass tank in 1.56 l volume with four plate electrode wasused to do experiments. the electrodes made of iron and connect to the positive and negative pole of dcpower supply (bipolar mode). the tank was filled with synthetic wastewater that was containingcadmium ion in concentration 5, 50 and 500 mg/l and then it was started up. the percent of cadmiumion removal was measured at ph 3, 7 and 10 and in electric potential range of 20, 30 and 40 volts. at theend of each stage of experiment, volume of produced sludge was measured. the results obtained atdifferent electrical potential showed that initial concentration of cadmium can effect on efficiencyremoval and for higher concentration of cadmium, higher electrical potential or more reaction time isneeded. on the other hand, if the initial concentration increases, the time required of process shouldincrease too. the final ph for iron electrodes was always higher than initial ph. as expected, the resultsshowed that for a given time, the removal efficiency increased significantly with increase of currentdensity. the highest electrical potential (40v) produced the quickest treatment with >99% cadmiumreduction occurring after only 20 min. the result showed that, in this process, the use of differentelectrical potentials can provide a wide range of ph for doing this process and electrocoagulationprocess (using iron electrodes) is a reliable, safety, efficient and cost-effective method for removal ofcadmium from industrial effluents, especially designed for ph =10 and voltage = 40v.