Preparation of W-doped titanium lithium ion sieve by hydrothermal method and enhanced adsorption performance for Li+

Abstract

Titanium lithium ion sieve (Ti-LIS) has attracted much attention due to their excellent adsorption properties and easy preparation process. In this study, the Li₂TiO₃ with different doping amounts of W (LTWO) was synthesized by the hydrothermal method. Then, the LTWO was washed with HCl to obtain the adsorbent of W-doped H₂TiO₃ (HTWO). The structure and adsorption properties of HTWO-4 were tested and the results showed that the introduction of W into HTWO leads to lattice defects, which increase oxygen vacancies and promote Li⁺ diffusion in the adsorbent. The effects of adsorption time, initial Li⁺ concentration, and pH on the adsorption properties of Li⁺ were systematically evaluated. The adsorption process of HTWO was confirmed as chemisorption and monolayer adsorption by simulating the pseudo-second-order kinetic model and Langmuir model. Among them, HTWO-4 exhibits a higher adsorption capacity than others, with a value of 34.68 mg/g in a LiCl solution (Li⁺  = 210 mg/L). Additionally, the HTWO-4 exhibits superior adsorption selectivity of Li⁺ over Mg²⁺, Ca²⁺, K⁺, and Na⁺, maintaining a high Li⁺ adsorption capacity after five regeneration cycles. This work provides an ideal candidate adsorbent in the field of lithium resource utilization.