Oxidative Stress Induced by Metal Ions in Bioleaching of LiCoO2 by an Acidophilic Microbial Consortium

The efficiency of bioleaching lithium and cobalt from waste lithium ion batteries (WLIBs) is significantly affected by the pulp density of cathode active materials. The bioleaching of Li and Co from lithium cobalt oxide (LiCoO2) under different pulp densities were investigated using an acidophilic microbial consortium (AMC). It was found that the highest metal recovery yields of 94.8% Li and 97.8% Co occurred at 4.0% (w·v-1) pulp density compared with 83.2% Li and 86.6% Co at 5.0% pulp density. Experimental results showed that there existed an effect of oxidative stress induced by metal ions in the leachate on the bio-oxidative activity of AMC, which also had a major impact on the morphology and the biomass amount of biofilms. Through the reactive oxygen species (ROS) regulation by an exogenous addition of glutathione (GSH), metal recovery yields of 98.1% Li and 96.3% Co from the bioleaching of LiCoO2 at 5.0% pulp density were obtained.