Cu2+, Fe2+ and Fe3+ analysis of bioleaching solutions using chronoamperometry and BDD electrode

In this work, a boron-doped diamond (BDD) electrode was evaluated for the electroanalytical determination of millimolar concentrations of Cu2+, Fe2+ and Fe3+ using chronoamperometry. The interfering role that each ion plays on the quantitative determination of other metal ion concentrations was also assessed. No interference from other metal ions was observed when Fe3+ and Fe2+ were analysed. By contrast, reduction of Fe3+ took place at the same potential where [Cu2+] was measured causing a minor interference to the Cu2+ signal. A multiple linear regression (MLR) calibration model was made for each analyte using real bioleaching samples, which demonstrated high coefficients of determination and adequate standard errors. The methods developed were used to monitor bioleaching of chalcopyrite for 4 months. The electroanalytical methods are particularly well-suited for analysing Cu2+, Fe3+ and Fe2+ concentration in acidic mine drainage (AMD) and bioleaching environments.