Selective ion channel adsorbents facilitate efficient and low environmental impact extraction of liquid lithium...

As lithium is the cornerstone of green energy development, it is crucial to realize a low environmental impact and efficient lithium extraction process. Ion-sieve adsorption is the most widely used method to extract liquid lithium resources, but this method is only efficient under alkaline conditions for H⁺ and Mg²⁺ competing adsorption. Conventional methods are often accompanied by the consumption of quantities of alkali, the generation of solid waste, and the acidification of liquid lithium resources. To address these issues, a selective ion-channel adsorbent was constructed. The composition comprises an ion sieve adsorbent and an organic carrier with a zwitterionic quaternary ammonium base group. This group storages OH^- in situ, hinders H⁺ diffusion, slows down Mg²⁺ diffusion, and accelerates Li⁺ diffusion by relying on the difference in binding energies, which reduces the competing adsorption and avoids acidification and solid waste generation. The saturated adsorption capacity (21.38 mg/g) and selectivity of the adsorbent are 4.7 and 24 times higher than that of conventional ion-sieve adsorbent under neutral conditions respectively. The dosage of alkali is 1/256 of the traditional method, the effluent remains neutral and no solid waste is generated. This study presents an environmental and effective adsorbent for lithium extraction.