Rates of Metal Electrodeposition from Aqueous Solutions in the Presence of Chelating Agents

The rates of Cu deposition from aqueous solutions containing chelating agents, such as citric acid, nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA), in an electrochemical membrane cell were measured. An equimolar solution of chelating agents and metals was examined. The iridium oxide and Pt coated on titanium electrodes were used as the anode and cathode, respectively. The cation-exchange membrane Neosepta CM-1 was used to separate the cathode and anode chambers. All experiments were carried out as a function of current density (18.5–139 A/m), initial catholyte pH (1–9), and metal concentration (10–80 mol/m). It was shown that the initial rates of Cu electrodeposition decreased in the order citrate . NTA . EDTA, which was not wholly related to the complexing ability of metals and the chelating agents.