Investigation of the Anodic Dissolution of Zinc in Sodium Chloride Electrolyte - A Green Process

The anodic dissolution of zinc electrodes in sodium chloride aqueous solution has been investigated experimentally. The effects of application of polarity reversal (PR), ultrasonic (US) enhancement, stirring, current density (CD), concentration and pH of the supporting electrolyte, and temperature of the bath were studied. The results revealed that application of PR increased the dissolution of Zn but the current was low. However, the application of US enhancement led to higher zinc dissolution accompanied with higher current efficiency (CE). The combination of US enhancement and stirring led to more dissolution of zinc. Increasing the current density and concentration of NaCl increased the dissolution of zinc and the current efficiency was almost constant. On the other hand, pH of the bath did not play a significant effect on the amount of the dissolved zinc or current efficiency. It was also observed that increasing the temperature from 10 degrees C to 40 degrees C led to a significant increase in the mass of the dissolved zinc and CE; but the increase of temperature from 40 degrees C to 50 or 60 degrees C, however, did not have a significant effect.