Process optimization of bioleaching for sustainable recovery of metals from waste lithium-ion batteries

This study uses bioleaching as a sustainable approach for metal extraction from waste lithium-ion batteries. Three microbial consortia (SC1, SC2, and SC3) were isolated from E-waste recycling-contaminated soils, which primarily belong to the Firmicutes phylum. Optimization of the bioleaching process was conducted by using response surface methodology, which revealed the high predictability. SC1 demonstrated the highest Li and Cu bioleaching efficiencies of 86 % and 87 %, respectively, using a 10 g/L pulp density and a 30 v/v% inoculum size over 48 h, whereas SC3 showed the maximum Co leaching efficiency of 42 %. Also, the kinetic studies revealed that the bioleaching process was well fitted with film diffusion-controlled mechanism. The study identifies SC1 as the most efficient microbial consortium for metal recovery from waste LiBs compared to others. This study highlights the potential of microorganisms for developing an eco-friendly, efficient bioleaching process for the sustainable recycling of metals from spent batteries.