Insights into Li+ adsorption using H2TiO3 in salt lakes with different hydrochemical types: The activity of OH groups

Adsorption-based lithium (Li) recovery from salt lakes has focused on Li+ selectivity in competitive cations and improving the adsorption capacity, but ignored the effect of different hydrochemical types on its adsorption. Herein, the adsorption behavior of Li+ was comparatively studied in carbonate-type, sulfate-type, and chloride-type salt lakes using H2TiO3 as an adsorbent. The Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy confirmed that the replacement of O-H by O-Li bond in H2TiO3 sieves drove the Li+ capture. At a salt concentration of 10 g/L, the adsorption of Li+ by H2TiO3 was in the order of SO42- (40.08 mg g(-1)) > Cl- (36.66 mg g(-1)) > CO32- (30.18 mg g(-1)). Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) demonstrated that the number of activated OH groups in the three salt solutions followed the same order of adsorption capacity. The binding energy of Li+ and anion calculated by density functional theory (DFT) verified the activity of OH groups, further revealing the influence mechanism of hydrochemical types on Li+ adsorption. This study suggests that the activity of Li+ adsorption sites was affected by the specific hydrochemical types of salt lakes, providing theoretical guidance for the Li+ adsorptive recovery from different water matrices.