Naseri, TannazTannazNaseriMousavi, Seyyed MohammadSeyyed MohammadMousaviLiese, AndreasAndreasLieseKuchta, KerstinKerstinKuchta2023-06-072023-06-072023-10-01Journal of Environmental Management 343: 118197 (2023-10-01)http://hdl.handle.net/11420/15369Despite the increased demand for resource recovery from spent lithium-ion batteries (LIBs), low Mn leaching efficiencies have hindered the development of this technology. A novel process was devised to enhance the dissolution of metals by producing citric acid using a molasses medium by Penicillium citrinum. This investigation used response surface methodology to investigate the influence of molasses concentration and media components on citric acid production, which demonstrated that molasses (18.5% w/w), KH2PO4 (3.8 g/L), MgSO4.7H2O (0.11 g/L), and methanol (1.2% (v/v)) were the optimum values leading to the production of 31.50 g/L citric acid. Afterward, optimum inhibitor concentrations (iodoacetic acid: 0.05 mM) were added to accumulate citric acid, resulting in maximum bio-production (40.12 g/L) of citric acid. The pulp density and leaching time effect on metals dissolution was investigated in enriched-citric acid spent medium. The suitable conditions were a pulp density of 70 g/L and a leaching duration of 6 days, which led to the highest dissolution of Mn (79%) and Li (90%). Based on the results of the TCLP tests, the bioleaching residue is non-hazardous, suitable for safe disposal, and does not pose an environmental threat. Moreover, nearly 98% of Mn was extracted from the bioleaching solution with oxalic acid at 1.2 M. XRD, and FE-SEM analyses were utilized for further bioleaching and precipitation mechanism analysis.en0301-47972023Citric acidMaxtimizationMolasses mediumPenicillium citrinumPrecipitationSpent lithium-ion batteriesJournal Article10.1016/j.jenvman.2023.11819737216767Journal Article