La electrodisolución de aluminio en soluciones conteniendo iones cloruros o sulfatos durante el proceso de electrocoagulación del lactosuero ácido, ha sido el objetivo de este trabajo. Los pH alcalinos aumentan la velocidad de disolución en varios órdenes de magnitud. El medio electrolítico (Cl- o SO4(2-)) no parece influir significativamente en la disolución de aluminio, pero aumentan la densidad de carga, que ayuda en el proceso electroquímico. Los resultados están relacionados con la naturaleza de las especies de hidróxidos de aluminio formados durante la disolución anódica. En condiciones ácidas y neutras, los iones OH- del cátodo no participan completamente en la formación de especies neutras de hidróxido de aluminio y el exceso de iones OH- aumenta el pH del medio. En contraste, el pH disminuye en condiciones altamente alcalinas atribuido al consumo de grandes cantidades de iones OH- para formar especies aniónicas, tales como Al(OH)4- y Al(OH)5(2-) y otras especies oligoméricas de aluminio.

Electrodissolution of aluminum in solutions containing chloride or sulfate ions during electrocoagulation acid whey, has been the objective of this work. The alkaline pH increases the rate of dissolution by several orders of magnitude. The electrolytic medium (Cl- or SO4(2-)) does not seem to significantly influence the dissolution of aluminum, but increase the charge density, which helps in the electrochemical process. The results are related to the nature of aluminum hydroxide species formed during anodic dissolution. In acidic and neutral conditions, OH-ions from the cathode do not fully participate in the formation of neutral species of aluminum hydroxide and excess OH-ions increases the pH of the medium. In contrast, the pH 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)5(2-), and other polymeric species of aluminun.

An electrochemical study of Co electrodeposition onto polycrystalline Pt from an aqueous solution containing 10-2 M CoCl2 + 1 M NH4CI (pH = 9.3) was conducted at overpotential conditions. The current density transients showed two maxima that corresponded to two nucleation and growth processes. The entire transient behavior was adequately predicted considering the contribution to the total current of four different processes: a Langmuir-type adsorption process, a diffusion-controlled two-dimensional instantaneous nucleation, and two three-dimensional nucleation and growth processes.