• 标题：Sandwiched liquid-membrane electrodialysis: Lithium selective recovery from salt lake brines with high Mg/Li ratio.
• 关键词：Electrodialysis;High Mg/Li ratio;Liquid membrane;Lithium extraction;Mg/Li separation
• 作者：

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A sandwiched liquid-membrane electrodialysis system, which combines the characteristics of liquid-membrane extraction and electrodialysis, has been proposed here to realize the selective extraction of lithium from salt-lake brines with high Mg/Li mass ratio. The sandwiched liquid membrane is comprised of 2 cation exchange membranes and a Li+-loaded organic liquid film. Because of the moderate working environment and satisfactory performance, the TBP + ClO 4 - system is chosen as the liquid film out of four candidates, namely TBP + FeCl 3 system, TBP + ClO 4 - system, N-butanol, and β-diketone. According to the electrodialysis experiments then, the Mg/Li ratio in catholyte is reduced to lower than 2 from 100 in the initial brine and the specific energy consumption is as low as 0.13 kWh·mol?1 Li. Additionally, the optimal voltage and temperature for the electrodialysis process are determined as 3.00 V and 20 °C. Finally, we also conclude that this approach is highly adaptable to brines with different cation compositions, because of its ability to separate Li+ with other impurity cations in brine (Na+, K+, Mg2+, and Ca2+). With high adaptability and low energy consumption, this sandwiched liquid-membrane electrodialysis system provides a promising perspective for lithium extraction and separation from brines with high Mg/Li ratio. Image 1 ? A sandwiched liquid-membrane electrodialysis system was proposed and studied. ? The Mg/Li ratio was reduced from 100 to 2 with energy consumption <130 Wh/mol Li. ? Impurity cations (Na+, K+, Mg2+, Ca2+) in brines can be efficiently separated.