A density functional theory insight into the extraction mechanism of lithium recovery from alkaline brine by β‐diketones

Abstract

AbstractIn this study, the mechanism of lithium extraction with β‐diketones was investigated by resolving the reaction mechanism, thermodynamic property, and molecular interaction through density functional theory approach. Before the selective extraction of lithium, the β‐diketones had tautomerism with the product of enol. The enol structure was unsteady in alkaline environment so that Li+can be selectively extracted by taking the place of hydroxyl hydrogen. Meanwhile, the synergistic effect of TOPO intensified the extraction ability by the generation of strong electrostatic. Based on the calculated Gibbs energy changes, the parameters of extraction efficiency and separation factor were analyzed and they had qualitative consistence with the experimental results. Meanwhile, it was determined that the electron‐withdrawing effect of the subsistent group in the β‐diketones had a critical influence on the extraction separation performance. Besides, the theoretical model predicted successfully the transition of extraction complex from hydrophilicity to lipophilicity after the combination with synergistic reagent.