Chromium (Cr+6) Removal from Aqueous Environments by Electrocoagulation Process Using Aluminum Electrodes

Document Type : Research Paper


1 Assist. Prof., School of Environmental Health, Tehran University of Medical Sciences

2 PhD Student of Environmental Health, Tehran University of Medical Sciences

3 Prof. of School of Environmental Health and Health Research Institute, Tehran University of Medical Sciences

4 Prof. of School of Environmental Health, Tehran University of Medical Sciences

5 Assoc. Prof., School of Environmental Health, Tehran University of Medical Sciences


The performance of electrocoagulation, with aluminum sacrificial anode, has been investigated. for removal of Cr (VI)), Several working parameters, such as pollutant concentration, pH, electrical potential, COD, turbidity, and reaction time were studied in an attempt to achieve higher removal efficiency levels. Solutions of varying chromium concentrations (5-50-500 ppm) were prepared. To follow the progress of the treatment, samples of 25ml were taken at 20 min intervals for up to 1 h and then filtered (0.45 μ) to eliminate sludge formed during electrolysis. The pH of the initial solution was also varied to study its effects on chromium removal efficiency. Results obtained with synthetic wastewater revealed that the most effective chromium removal efficiency could be achieved when a constant pH level of 3 was maintained. In addition, increased electrical potential, within the range of 20-40V, enhanced treatment rate without affecting the charge loading, but required reduced metal ion concentrations to below admissible standard levels. The process was successfully applied to the treatment of an electroplating wastewater where an effective reduction of Cr (VI) concentration below standard limits was obtained just after 20-60 min. The method was found to be highly efficient and relatively fast compared to conventional techniques. Thus, it may be concluded that electrocoagulation process has the potential to be utilized for the cost-effective removal of heavy metals from water and wastewater.


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