Effect of Electrocoagulation Parameters on Chromium Removal, Sludge Settling, and Energy Consumption

Wastewater laden with toxic pollutants, such as chromium (Cr), can hurt humans, the environment, and aquatic life if not properly treated. The present work proposes to study the elimination of 100 mg/l of Cr(VI) ions from a synthetic wastewater effluent using a dynamic electrocoagulation process employing aluminum electrodes. The influences of several parameters are explored for the electrocoagulation process effectiveness in terms of Cr removal yield. This was done within the following ranges:  current density (5-22 mA/cm2), initial pH (2-7), and chromium concentration (25-150 mg/l). A settling step was followed to determine the total suspended solids content and the sludge volume index after electrocoagulation treatment. Depending on the operating conditions, the data of specific electrical energy consumption were employed to determine the best operating parameters of the process efficiency. Furthermore, data analysis (Scanning Electron Microscope, Fourier Transform Infrared spectroscopy, X-ray diffraction analysis, and X-ray fluorescence) of sludge formed after electrocoagulation showed an amorphous nature with a high content of aluminum and function groups that should have a potential to be utilized as coagulant/sorbent in wastewater treatment.