Metal release from stainless steel electrodes of a PEF treatment chamber

The effect of electrical parameters (field strength E and total specific energy input WT) and product factors (type, electrical conductivity and pH) on the metal release from the electrodes of a continuous flow parallel plate PEF chamber into the treatment medium, was investigated. Experiments were carried out by subjecting two different treatment buffer solutions (McIlvaine and Trizma-HCl) with different values of pH (3.5 and 7) and electrical conductivities ċ (2 and 3.5 mS/cm) to PEF treatments of different intensity (E=12-31 kV/cm, WT=20-100 J/mL). For each experiment, the concentration of the five main elements of stainless steel (iron, chromium, nickel, molybdenum and manganese) were detected by ICPMS technique. Results showed that the magnitude of the material transferred from the electrodes into the treatment medium depends on the PEF treatment intensity. In particular, for each field strength applied, the metal concentration was found to increase with the increase of total specific energy input. When the total energy input was kept constant, it was noticed that metal concentration decreased with increasing the field strength applied as a result of the increase of treatment frequency. Moreover, results have also showed that the extent of the electrochemical phenomenon at the electrode-solution interface markedly depends on the composition and pH of the treatment medium and only slightly by its electrical conductivity.