Accelerating the adsorption kinetics of layer-structured TiO2·H2O adsorbents for selectively separating Li+ from low-grade brines via Ce doping

The layer-structured titanium oxide lithium ion sieve (TiO 2 ·H 2 O) is regarded as one of the most promising adsorbents for recovering Li + from low-grade brines with high Mg 2+ /Li + ratios and low lithium concentrations. This is due to its exceptional theoretical lithium adsorption capacity and outstanding stability. Nevertheless, its prolonged adsorption equilibrium time, frequently in excess of 72 h, has constrained its large-scale practical application, thus confining its utilization primarily to laboratory settings. To address this challenge, we have developed a Ce-doped TiO 2 ·H 2 O adsorbent through a simple in-situ calcination method. The as-prepared adsorbents have been shown to achieve a high adsorption capacity of up to 58.42 mg/g within 10 h in a 700 ppm LiOH solution, while exhibiting a very low Ti 4+ dissolution loss rate of around 0.6 %. It is noteworthy that the Ce doping process resulted in a 14 % enhancement in adsorption capacity, accompanied by a substantial improvement in the desorption/adsorption kinetics and selectivity of the TiO 2 ·H 2 O lithium adsorbents. In summary, this study presents a novel methodology for accelerating the Li + sorption in Ti–O frameworks derived from natural brines, which provides valuable insights for enhancing the practical applicability of TiO 2 ·H 2 O.