Electrochemical behavior of massive chalcopyrite bioleached electrodes in presence of silver at 35 °C

The electrochemical response of massive chalcopyrite electrodes bioleached with mesophile microorganisms in both presence and absence of Ag(I) ions was studied using linear and cyclic voltammetry. The electrolyte employed for the electrochemical tests was the medium used to bioleaching the electrodes (3.0 g/L (NH4)2·SO4, 0.5 g/L K2HPO4, 0.5 g/L MgSO4·7H2O and 0.1 g/L Ca(NO3)2).The results showed small differences in voltagramms carried out in presence and absence of Ag(I): In bioleached electrodes tested in presence of Ag(I) ions, the anodic and cathodic current signals were bigger than when Ag(I) ions were not present. Moreover, the passivation of chalcopyrite occurred at two different times: First, the passivation was observed in the bioleached electrodes in absence of Ag(I) and after in the bioleached electrodes in presence of Ag(I). The pre-wave observed in the anodic dissolution of the chalcopyrite was not seen in the bioleached electrodes in absence of Ag(I) ions, but in the electrode treated with bacteria in presence of Ag(I) ions an increase in current signals was observed.