Efficiencies of electrolytic treatment of complexed metal solutions in a stirred cell having a membrane separator

Electrolytic recovery of metals such as Cu(II) and strong chelating agents such as EDTA (ethylenediaminetetraacetic acid) from their equimolar complex ed solutions was investigated in a stirred cell having a membrane separator . The iridium oxide coated on titanium (IrO2/Ti) was used as the anode. Exp eriments were performed as a function of membrane-type (Neosepta CM-1 and C M-2), current density (18.5-185 A/m(2)), cathode material (Pt plate, Pt/Ti, Cu plate, stainless steel), initial catholyte pH (1-9) and initial Cu-EDTA chelate concentration (0.01-0.08 M), and initial anolyte NaNO3 concentrati on (0.1-0.8 M). An economically feasible current efficiency (>60%) and meta l recovery (>95%) could be obtained if the Cu-EDTA chelate concentration wa s sufficiently high. Electrodeposition of other divalent metals including P b, Hg, and Cd onto Pt/Ti cathode from their EDTA solutions was possible, bu t no apparent deposition of Co, Ni Zn, and Mn was observed. (C) 2000 Elsevi er Science B.V. All rights reserved.