Advances and promotion strategies of membrane-based methods for extracting lithium from brine

The importance of lithium resources has gradually increased with the research and promotion of lithium batteries. Lithium extraction from salt lake has become a major trend due to the abundance of lithium resources. However, there are plenty of interfering ions in the brine, especially magnesium ions containing concentration ratios of several to tens, which are difficult to separate due to the similar radius of hydrated ions. And membrane method has the advantages of being environmentally friendly, simple, and good separation effect, which is an important research direction for lithium extraction from salt lake. This paper presents a comprehensive overview of several common membrane-based methods for lithium separation, especially focusing on pressure-driven and electric-driven methods, and a comprehensive assessment of advantages and disadvantages between the different methods in terms of lithium extraction efficiency, durability, energy consumption, environmental friendliness, and technological maturity. The shortcomings of them are also presented, for example, current processes are still limited by membrane lifetime, device cost, separation efficiency, and the processes are not mature enough to achieve a complete process from source to product. Therefore, the future directions are focused on membrane materials, membrane antifouling performance, process development, and process integrity testing.