Electrochemically Dissolved Aluminum Coagulants for the Removal of Natural Organic Matter from Synthetic and Real Industrial Wastewaters

Abstract

In this work, the effects of some experimental parameters (supporting electrolyte, current density, and initial pH) on the anodic dissolution of aluminum and on the electrocoagulation of tannic acid aqueous solutions as well as real industrial wastewaters containing tannic acid were investigated. Experimental results indicated that both chemical and electrochemical dissolution play an important role in the formation of hydroxo-aluminum species. The chemical dissolution of aluminum is strongly influenced by the solution pH. Corrosion studies have demonstrated that the presence of chloride ions in water accelerates dissolution of aluminum by pitting corrosion while phosphate ions inhibit the corrosion of aluminum by formation of a thick passive layer of aluminum hydroxide/phosphate on the aluminum surface. The results obtained can be used to better understand the mechanism of the electrocoagulation process due to the importance of the anode surface electrodissolution in the treatment process. Electrocoagula...