Chromium Removal by Electrocoagulation

Abstract

Electrocoagulation is an effective process for the destabilization of finely dispersed particles by removing hydrocarbons, greases, suspended solids, and heavy metals from different types of waste water. People have long been trying to find a cost effective and reliable way to treat waste water and electrocoagulation is one of this ways to treat waste water. Using electrocoagulation to remove hexavalent chromium involves reducing hexavalent chromium to its insoluble trivalent form and precipitating it as a hydroxide or oxy hydroxide. Synthetic solutions of varying chromium concentrations (5-20-50 ppm) were prepared. Results obtained with synthetic wastewater in batch process revealed that the most effective removal capacities of the studied metals could be achieved when the pH was kept at 3, initial concentration 20 ppm, time taken 30 min and voltage at 13V. In addition, the increases of electrical potential in the range of 3-13 V. Batch and Continuous study were carried out at laboratory scale. Laboratory Scale experiments were conducted for different pH range for different electrode configuration and different flow rate. Electrocoagulation was able to bring down chromium concentration Efficiency was achieved up to 94%. Removal efficiency of chromium with Aluminum electrodes is lower than Iron electrode. The energy consumption is lower with Iron electrode, while the electrode consumption is lower with Aluminum electrode. Electrocoagulation particularly viable is that it is three times cheaper than other purification method. Also, it can be conclude that the electrocoagulation process has the potential to be utilized for cost – effective removal of heavy metals from water and wastewater. The results suggest that electrocoagulation can be used effectively for the removal of Cr (VI).