Urban Mining of Rare Earth Elements from Fluorescent Lamp Recycling Waste via Acidithiobacillus thiooxidans : A Sustainable and High-Performance Bioleaching Approach

High Resolution Image Download MS PowerPoint Slide Rare earth elements (REEs) are critical for modern technologies, yet their sustainable recycling from electronic waste remains a significant challenge. While bioleaching presents a green alternative to conventional hydrometallurgy, its efficiency for complex real wastes is often limited. This study pioneers the application of the acidophilic bacterium Acidithiobacillus thiooxidans for the bioleaching of industrial fluorescent lamp waste (FLW). Results demonstrate that both one and two-step bioleaching approaches successfully achieved complete solubilization of yttrium and europium, which constitute over 95% of the REE content in this residue. The two-step process, particularly in baffled flasks, showed superior performance, achieving near-complete extraction (>98%) of Y and Eu in approximately three days. This represents the most efficient bioleaching strategy reported to date for FLW. Inhibition assays revealed that the bacterial growth is specifically suppressed by Y 3+ and La 3+ ions. Furthermore, the study successfully closed the recycling loop by upcycling the leached REEs into a high-value functional product. Through selective oxalate precipitation and subsequent thermal decomposition, we synthesized Y 2 O 3:Eu 3+ phosphors with excellent luminescent properties and 96% purity. These findings offer crucial insights for process optimization and establish a promising, environmentally sustainable biotechnology for REE recovery within a circular economy framework.