Lithium Recovery from Brines: A Comprehensive Review of Advanced Separation Technologies

The increasing lithium (Li) demand, attributable to its essential function in energy storage applications, has necessitated the advancement in Li extraction and recovery methods. Brine-based Li extraction presents a cost-effective and scalable solution; however, challenges such as high magnesium-to-Li (Mg/Li) ratios and environmental concerns necessitate innovative approaches. This review comprehensively examines various Li recovery techniques from brine, focusing on precipitation, adsorption and ion exchange, membrane separation, electrochemical separation, solvent extraction, and hybrid technologies. Precipitation methods, including carbonate and aluminate precipitation, offer straightforward processing but face selectivity challenges in high Mg/Li ratio brines. Adsorption and ion exchange techniques, particularly Li-ion sieves and layered double hydroxides, have demonstrated high selectivity and efficiency. Electrochemical methods present promising low-energy alternatives for Li separation. Furthermore, solvent extraction and advanced membrane-based techniques provide additional pathways for Li recovery, enhancing the yield and purity. This Perspective highlights recent advancements, process optimizations, and emerging strategies aimed at improving Li recovery while reducing environmental impact. Comparative assessment of these techniques is provided, considering factors such as the Mg/Li ratio, operational feasibility, energy consumption, and scalability. Special emphasis is placed on emerging strategies such as engineered sorbents, electrochemical separation, and advanced membrane filtration, which offer sustainable alternatives to traditional methods. Additionally, this review bridges the gap between laboratory-scale research and industrial applications, outlining key challenges and potential solutions for Li extraction. This Review provides a roadmap for developing more efficient, sustainable, and scalable Li extraction processes. The insights presented here aid researchers, industry professionals, and policymakers in advancing Li recovery technologies to meet growing global demand.