Bioelectrochemical metal recovery can in principle be applied to many metal-rich streams, using a variety of reactions. For the anode reaction, BioelectroMET will assess two inorganic electron donors present in leachates, Fe(II) and thiosulfate. In addition, BioelectroMET will evaluate the use of organic streams available at metallurgical sites. For the cathode reaction, the reduction of several metals will be considered.
The table below shows the different electrochemical couples that can be considered at each side of the bioelectrochemical cells. The difference between their potentials indicates if the overall process is producing energy or if on the contrary, external energy input is required.
|Anodic Oxidation Reaction||E0 (V vs NHE)||E (V vs NHE)|
|Acetate||C2H3O2- + 4 H2O → 2 HCO3- + 9 H+ + 8 e-||0.19||-0.29|
|Thiosulphate||S2O32- + 5 H2O → 2 SO42- + 10 H+ + 8 e-||0.28||0.20|
|Iron||Fe2+ → Fe3+||0.77||0.83|
|Copper||Cu2+ + 2 e- → Cu||0.34||0.30|
|Zinc||Zn2+ + 2 e- → Zn||-0.76||-0.80|
|Nickel||Ni2+ + 2 e- → Ni||-0.26||-0.30|
|Iron||Fe3+ + e- → Fe2+||0.77||0.83|
|Iron||Fe2+ + 2 e- → Fe||-0.44||-0.48|
|Cobalt||Co2+ + 2 e- → Co||-0.28||-0.32|
|Lead||Pb2+ + 2 e- → Pb||-0.13||-0.17|