Electrode Passivation in the Electrocoagulation Process

One of the main limiting factors of the electrocoagulation, as a process of treatment for remotion of contaminants from residual waters, is not knowing the degree of interaction of some variables which could significantly affect the system. The electrode passivation is one of them once its presence limits the emission of metallic ions and consequently the treatment time is increased as well as cost, and remotion efficiency is decreased. In the present work potentiodynamic and potentiostatic curves were used to observe the behaviour of current density vs. pH, electrical conductivity, distance between electrodes, auxiliary electrode area and applied potential difference. We found out that all the above variables influence the current density, that passivation is at 50 mV, independently of all the other variables, and that at 2000 mV, only is observed when pH = 2 and high electrical conductivities.