Bioelectrochemical recovery of ammonia–copper(II) complexes from wastewater using a dual chamber microbial fuel cell

Abstract: The cathodic reduction of complex-state copper(II) was investigated in a dual chamber microbial fuel cell (MFC). The inner resistance of MFC system could be reduced in the presence of ionizing , however, mass transfer was hindered at higher ammonia concentration. Thermodynamic and electrochemical analyses indicated that the processes of complex dissociation and copper reduction were governed by the ratio of T[Cu]:T[NH3] and the pH of solution. The reduction of could be achieved via two possible pathways: (1) releasing Cu2+ from , then reducing Cu2+ to Cu or Cu2O and (2) accepting an electron and forming , and depositing as Cu or Cu2O consequently. At initial concentration of 350mg T[Cu] L−1, copper removal efficiency of 96% was obtained at pH=9.0 within 12h (with △Cu/△COD=1.24), 84% was obtained at pH=3.0 within 8h (with △Cu/△COD=1.72). was reduced as polyhedral deposits on the cathode. [Copyright &y& Elsevier]