Electrodissolution of aluminum electrodes during electrocoagulation of an acid whey.

Electrodissolution of aluminum in solutions containing chloride or sulfate ions during electrocoagulation acid whey, has been the objective of thiswork. The alkaline pH increases the rate of dissolution by several orders of magnitude. The electrolytic medium (Cl- or SO42-) does not seem tosignificantly influence the dissolution of aluminum, but increase the charge density, which helps in the electrochemical process. The results arerelated to the nature of aluminum hydroxide species formed during anodic dissolution. In acidic and neutral conditions, OH-ions from the cathode donot fully participate in the formation of neutral species of aluminum hydroxide and excess OH-ions increases the pH of the medium. In contrast, thepH decreases in highly alkaline conditions attributed to the consumption of large amounts of OH- ions to form an anionic species such as Al(OH)4-and Al(OH)52-, and other polymeric species of aluminun.