Determination of Copper Dissolution Activation Energy in Concentrated Hydrogen Peroxide

Abstract

Determination of copper dissolution activation energy in concentrated hydrogen peroxide used as a decontaminant agent on aircraft has been carried out. This work was performed in conjunction with the determination of the effect of hydrogen peroxide used as a decontaminant agent on selected aircraft metallic materials. The main idea of this work was to simulate the worst possible condition, i.e. spillage of the liquid concentrate due to operator abuse or conditions where large-scale condensation of the peroxide takes place due to the failure of decontamination process control. Due to inherent properties of the chemical used as a decontaminant agent, it possibly could affect the airliner metallic materials during or after the decontamination process, particularly copper. Since copper is one of the important alloying elements in the aluminum alloys, this work was performed to get the idea how fast the process takes place and so to help understanding the subsequent corrosion process, if any, on the aircraft’s flightworthiness at least qualitatively and ideally quantitatively. The results showed that the rate of copper dissolution increased for the first 15 minutes of the reaction time with an activation energy of 19 kJ/mol, and then the fraction of copper dissolved became constant. This constant dissolution was expected to be due to the formation of copper hydroxide, which was observed to precipitate after the solution settled for some time. However, because the final consumption of hydrogen peroxide was not controlled, the exact reason for this constant dissolution cannot be determined at this time. The value of activation energy is within the range of activation energy found in the literature for other dissolution process. The low activation energy for dissolution of pure copper correlates with the observation of dissolution of copper from intermetallic particles in the aluminum alloys.