Microenvironment-Modulating Adsorption Enables Highly Efficient Lithium Extraction under Natural pH Conditions
Han Yu, Jiaxiang Ma, Dongqing Liu, Yan Yang, Tao Zhang, Min Wang, Daxin Liang, Liping Wen, Jun Ma, Wei Wang
Abstract
Ion-sieve adsorbents are effective materials in practical applications for extracting liquid lithium. However, it is greatly suppressed in adsorption capacity and selectivity (Li/Mg) under natural near-neutral conditions of seawater or salt lakes, due to the interference of in situ released H + and Mg 2+ impurity. This paper proposes an adsorbent with a microenvironment-modulating function as a solution. The introduction of quaternary ammonium groups into the carrier accelerates the migration of H +, while preventing the diffusion of Mg 2+ by electrostatic repulsion. Besides, it can also prestore OH –, effectively consuming the generated hydrogen ions in situ . Based on the rational design, the alkali consumption of the microenvironment-modulating strategy is dramatically reduced to 1/144 of the traditional alkali-adding method. Additionally, adsorption performance is significantly promoted under natural pH conditions, with a maximum 33 times higher separation factor (selectivity) and 4 times higher adsorption capacity than commercial ion-sieve adsorbents. This development indicates the feasibility of using microenvironment modulation for effective lithium extraction and inspires the development of next-generation high-performance adsorbents.