Preparation of zirconium oxide surface-modified magnetic lithium-ion sieves and selectivity mechanism analysis for lithium extraction from salt-lake brine based on the first principle

The increasing need for lithium (Li) resources requires the creation of effective extraction methods. Lithium-ion sieves have shown promise as adsorption materials; however, their ultrafine powder properties and poor cycle performance limit their industrial application. In this study, a new lithium-ion sieve named ZrO2@HMFO, which consists of zirconium oxide-coated magnetic manganese (Mn), was investigated. The absorption and desorption of Li by ZrO2@HMFO in a LiCl solution were studied. The adsorption capacity of ZrO2@HMFO was 35.8 mg/g, and it led to a decrease in the dissolution of manganese (Mn) and iron (Fe) to 1.11 % and 0.49 %, respectively. The combination of metal cation doping and coating significantly reduces the dissolution loss of Mn. Density functional theory (DFT) was employed to analyze the mechanism of selective Li+ extraction. Analysis of hydration energy, migration energy barrier, and adsorption energy revealed that Li ions were the most selectively adsorbed. Additionally, the increase in selectivity was confirmed by calculating that Fe doping increases the energy required for other metal cations to replace Hydrogen ions (H+) or Lithium ions (Li+). Thus, ZrO2@HMFO allows for easy separation and stable circulation, making it a promising material for efficient Li+ separation in salt-lake brine. The study of the selectivity mechanism also provides theoretical guidance for improving the selectivity of lithium-ion sieves in future research.