Synthesis and optimisation mechanism of functionalised adsorption materials for lithium-ion extraction from salt water: A review

Industrial applications, such as lithium-ion batteries (LIBs), have an increasing demand for lithium products, and the recovery of lithium plays an important role in the industrial cycle of lithium products. Extracting lithium from low-concentration solutions such as salt lakes and leachate is a challenge that is difficult to overcome at present. Adsorbents have excellent adsorption capacity and selectivity, and its simple preparation, low synthesis pollution and repeatability make it highly efficient whilst maintaining excellent economic advantages. However, reviews on lithium adsorbents are few, and they only focus on the types and properties of adsorbents. The synthesis scheme, improvement mechanism, thinking process and industrialisation of adsorbents have yet to be reviewed and analysed. To fill this gap, the topics above, including the selective adsorption mechanism and adsorption properties of lithium adsorbents, were reviewed and analysed in this study. The advantages and challenges of different adsorbents and their preparation schemes were discussed, optimisation techniques and mechanism for different preparation schemes were proposed. Under the same scheme, the similarities of various methods were summarised, the mechanism and thinking process of innovative preparation methods were analysed. The processing and application of powdered adsorbent materials were reviewed. Future development directions of adsorbent materials were also proposed.