Rates of metal electrodeposition from aqueous solutions in the presence ofchelating agents

The rates of Cu deposition from aqueous solutions containing cheating agent s, such as citric acid, nitrilotriacetic acid (NTA), and ethylenediaminetet raacetic acid (EDTA), in an electrochemical membrane cell were measured. An equimolar solution of chelating agents and metals was examined. The iridiu m oxide and Pt coated on titanium electrodes were used as the anode and cat hode, respectively. The cation-exchange membrane Neosepta CM-1 was used to separate the cathode and anode chambers. All experiments were carried out a s a function of current density (18.5-139 A/m(2)), initial catholyte pH (1- 9), and metal concentration (10-80 mol/m(3)). 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 c helating agents.