Microbial fuel cells coupled with the bioleaching technique that enhances the recovery of Cu from the secondary mine tailings in the bio-electrochemical system

Improper management of dumped tailings not only causes a potential waste of resources but also poses a direct threat to the lives of local residents. A dual-chamber microbial fuel cell (MFC) combining with the bioleaching technique was used in the study to extract Cu from the secondary mine tailings at a fed-batch scale. A mixed culture of acidophilic bacteria was enriched and isolated from the acidic drainage in a copper mine. The effects of the pulp densities and initial pH on both the bio-electronic performances and the recoveries of Cu on bio-electrochemical platform were comparatively investigated. An appropriate increase in the pulp densities and a suitable decrease in the initial pH facilitated increases in power generations and enhanced the recoveries of Cu from the tailing samples. The maximum power density of 30.54 mW/m(2) was achieved in the coupling system with the coulomb efficiency of 4.52%, and the internal resistance of 166.58 omega being synchronously obtained. Correspondingly, the highest recovery efficiency of Cu of 78.72% was got in the two-dimensional tests under conditions including the pulp density (w/v) of 20% and the initial pH of 1.8. The electrochemical reduction and the chemical precipitation in MFCs were confirmed as two of main mechanisms in obviously influencing the recovery of Cu. (c) 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019