Copper Dissolution Behavior in Acidic Iodate Solutions

Abstract

Copper dissolution was investigated using electrochemical techniques including potentiodynamic scans and electrochemical quartz crystal analysis. The adsorption of iodate on a copper surface depends on the solution pH and the concentration of iodate. IO3- behaves both as an oxidizer and a passivating agent for copper dissolution. At low IO3- concentrations, IO3- acts more like an oxidizer while it passivates the copper surface at higher concentrations. The copper dissolution rate decreases with increasing solution pH and increases with increasing concentration of potassium iodate up to 1 wt %. The dissolution rate does not change significantly when the potassium iodate concentration is >1 wt %. A strong adsorption of IO3- ions on a copper surface has been observed at higher solution pH's and higher iodate concentrations. This may be ascribed to the formation of a thin film of Cu(IO3)2 due to the high surface Cu2+ concentration and higher concentration of IO3- adjacent to the copper surface.