Copper catalysis for enhancement of cobalt leaching and acid utilization efficiency in microbial fuel cells

•Species of Cu(II) improved cobalt leaching and acid utilization efficiencies in MFCs.•A pH of 2.0 was more preferable than 3.0 for Cu(II)-catalyzed cobalt leaching in MFCs.•A solid/liquid ratio of 100–200mg/L was matched with a Cu(II) dosage of 10mg/L.•The estimated Ea for Cu(II)-catalyzed cobalt leaching in MFCs was 11.8kJ/mol. Enhancement of both cobalt leaching from LiCoO2 and acid utilization efficiency (AUE) in microbial fuel cells (MFCs) was successfully achieved by the addition of Cu(II). A dosage of 10mg/L Cu(II) improved both cobalt leaching up to 308% and AUE of 171% compared to the controls with no presence of Cu(II). The apparent activation energy of cobalt leaching catalyzed by Cu(II) in MFCs was only 11.8kJ/mol. These results demonstrate cobalt leaching in MFCs using Cu(II) as a catalyst may be an effective strategy for cobalt recovery and recycle of spent Li-ion batteries, and the evidence of influence factors including solid/liquid ratio, temperature, and pH and solution conductivity can contribute to improving understanding of and optimizing cobalt leaching catalyzed by Cu(II) in MFCs.