Sulfonate-functionalized MIL-101 with high lithium adsorption capacity and selectivity

With the booming development of the new energy industry, the demand for lithium resources has increased dramatically. Adsorption is a green and inexpensive process for lithium extraction from saline lakes but current commercial adsorbents generally have low adsorption capacity and poor stability, and are difficult to be applied to the purification of high-concentration lithium salts. Herein, we report an adsorbent, sulfonate-modified MIL-101(Cr) (MIL-101(Cr)-SO 3 H), for the efficient extraction of lithium from brine and highly concentrated lithium solution. It has high adsorption capacity (118.2 mg g −1 ) on Li + adsorption and fast kinetics (3.5 h to achieve full adsorption equilibrium). Detailed investigations clarify that the adsorption follows the Freundlich model in a spontaneous manner. The adsorption mechanisms of MIL-101(Cr)-SO 3 H for Li⁺ primarily include physical adsorption, chemical adsorption, and functional group adsorption. Such capacity is demonstrated with high durability and selectivity, indicating MIL-101(Cr)-SO 3 H is a promising adsorbent for Li  +  recycling and extraction.