Selective extraction of lithium from shale gas produced water using an aluminum-based adsorbent

Two-dimensional layered aluminum-based adsorbents have been developed and successfully applied to enrich low-concentration lithium from shale gas produced water. The adsorbent, synthesized with a lithium-to-aluminum molar ratio of 0.6 in the salt solution, demonstrated exceptional performance characteristics. Its structure, featuring nano-encapsulated layers, facilitated lithium insertion, enhanced the surface area, and optimized pore size distribution for efficient adsorption. The adsorption equilibrium was reached within 60 min, closely aligning with the pseudo-second-order model. The isotherm analysis, based on the Sips model, suggested a non-homogeneous multilayer adsorption process. Additionally, the adsorbent showed exceptional selectivity for Li+ over Na+, Ca2+, and Mg2+, ensuring effective lithium enrichment. Further desorption studies indicated that optimal conditions involved using deionized water at 333 K with a liquid-to-solid ratio of 80 mL/g. The adsorbent maintained robust performance and structural integrity through five adsorption–desorption cycles, highlighting its potential for recyclability and practical application in lithium recovery. These developments represent significant progress in harnessing lithium resources from shale gas produced water, thereby supporting advancements in clean energy technologies.