生物淋滤技术回收废旧锂离子电池中有价金属的微生物代谢机理及多金属抗性研究

Disposal of spent lithium-ion batteries is one of the most significant environmental issues to be addressed. Proper treatment of spent batteries will not only avoid the destruction of environmental ecology, but also solve the shortage of valuable metal resources. With the continuous improvement of battery energy density, the compositions of cathode materials become increasingly complicated, which will put a greater challenge to the current recycling technology. Owing to the merits of lower energy consumption and less pollution, bioleaching strategy is regarded as one of the most promising battery recycling technologies. However, its practical application is mainly subject to the cultivation of highly efficient microorganisms. The current research focuses on employing pure culture to cope with single cathode material and suffers from unstable bioleaching efficiencies and unclear metabolic mechanism, meanwhile lacking of reasonable regeneration of valuable metals. Therefore, this project aims to adopt bioleaching strategy, employ enriched mixed microorganisms to deal with complicated spent cathode material system, and investigate the relationships among operational parameters, metal leaching efficiencies and microorganism replacement mechanism. Combined with electrochemical deposition of valuable heavy metals (e.g. nickel, cobalt and manganese), the successful fabrication of high-capacity battery materials will significantly reduce the metallic biotoxicities and greatly realize the efficient utilization of recycling resources. Particularly, metagenomic and metatranscriptomic approaches will be applied to reveal the microbial metabolic mechanisms and multi-metallic resistance in the bioleaching process. This will definitely provide solid theoretical basis and technical support for process optimization and manipulation in recovering valuable metals from spent lithium-ion batteries.

废旧锂离子电池的处置是亟待解决的环境问题之一。合理处置废旧电池，既能避免生态环境遭受破坏，也能解决稀有金属资源短缺问题。随着电池能量密度的不断提升，电池的正极材料呈现出多元化和复杂化趋势，这对回收技术提出了新的挑战。生物淋滤法具有能耗低、污染小等优势，被誉为最有潜力的电池回收技术之一。然而，该技术的应用受制于高效微生物菌群的培养，目前的研究主要局限于单一菌株处理单一材料，存在金属浸出效率不稳定、菌群代谢机制不清晰等问题，此外有价金属的回用效率也有待提高。本项目拟采用生物淋滤法富集混合菌群处置废旧正极材料，探究环境因子与金属浸出效率，以及菌群更替规律的联系，结合电化学沉积法富集有价金属（镍、钴、锰），制备高容量电极材料，从而降低重金属的生物毒性，并实现资源的高效利用。同时利用宏基因组和宏转录组等微生物多组学手段，揭示菌群的代谢机理和多金属耐受机制，为该技术的优化和调控提供理论依据和技术支撑。

废旧锂离子电池的处置是亟待解决的环境问题之一。合理处置废旧锂离子电池，不仅能避免生态环境遭受破坏，而且能解决宝贵资源短缺问题。生物淋滤法具有能耗低、污染小等优势，被誉为最有潜力的电池回收技术之一。然而，来源于酸性环境的淋滤菌群或菌株存在淋滤周期长、淋滤效率低以及对有机化合物的耐受性差等问题，导致其不能适应复杂环境，难以大规模应用。此外，人们对生物淋滤菌群物种之间的相互作用关系仍然知之甚少。本项目采用生物淋滤法富集混合菌群处置废旧正极材料，采集了多个污水处理厂的活性污泥作为种泥，富集到具有多金属抗性的新型生物淋滤菌群，并研究其对锰酸锂等电极材料的淋滤效率，其中以氧化亚铁硫杆菌为主的嗜酸硫杆菌对锰酸锂的浸出效率较高，7天内可浸出78.10%的锂和85.16%的锰。利用基于高通量测序技术的宏基因组测序与比较基因组学分析，揭示了本项目富集的菌株与已报道的淋滤菌株在遗传信息多样性方面的差异，为生物淋滤法进一步在复杂环境中的应用奠定基础。该研究结果拓宽了人们对来自非酸性环境的生物淋滤细菌多样性的理解，并获得了可能在复杂环境中具有高效淋滤功能的新型淋滤菌群和菌株。同时，本项目建立了嗜酸性硫杆菌属及氧化亚铁硫杆菌种特异性PCR引物的设计及淋滤菌群快速鉴定方法；发现了潜在的新型生物淋滤菌种3种；并分离到包括氧化亚铁硫杆菌、嗜酸性菌属和硫化杆菌属的数株纯培养物；阐明了新型生物淋滤菌群中混合营养型和化能自养型菌群在淋滤过程中的互作机制。研究结果为生物淋滤法的优化和调控提供了理论依据和技术支撑。