Configuring 5TiO2·2H2O/C composite-type adsorbents for effectively recovering Li+ from original Salt Lake brines

Spinel-structured titanium‑lithium adsorbents have emerged as a promising solution for efficiently recovering Li + from Salt Lake brines with high Mg/Li ratio, owing to their stable structure, minimal dissolution loss, and excellent cycling stability. However, their practical application remains limited due to low adsorption capacity and prolonged equilibration times. In this study, we developed a novel 5TiO 2 ·2H 2 O/C adsorbents, synthesized by eluting Li 4 Ti 5 O 12 /C precursors with 0.15 mol/L HCl, which exhibits high adsorption capacity and minimal dissolution loss. Under optimal conditions, the 5TiO 2 ·2H 2 O/C adsorbents reached adsorption equilibrium within 5 h at 60 °C in a 600 ppm LiOH solution, with a maximum adsorption capacity of 41.84 mg/g and a titanium dissolution loss of only 0.29 %. The adsorption selectivity of the 5TiO 2 ·2H 2 O/C adsorbents was found to be strongly pH-dependent. In a 170 ppm Li + solution, the adsorbents demonstrated superior cycling stability in original Salt Lake brines, outperforming those in LiCl and Li 2 SO 4 solutions. This study provides valuable insights into the formation and mechanisms of action of these adsorbents, offering significant implications for the efficient recovery of Li + from various brines.