Efficient magnesium-lithium separation is a critical step in extracting lithium ions from salt lakes brine. Precipitation of Mg2+ from liquid to solid is the simplest separation method, but a side reaction of Li+ adsorption by precipitated floc leads to incomplete Mg/Li separation and lithium loss. In this study, we grafted phosphorus atomic sites onto silica-based nuclei with self-floating separation capability to prepare adsorbents with specific capture ability for Mg2+, achieving efficient Mg/Li separation from brine. Surface composition analysis shows that the content of P element is 0.99 %, which contributed 82.20 mg g⁻1 of Mg2+ adsorption capacity of at room temperature. During this process, the content of Na and Ca elements in the material decreased by 1.47 % and 0.85 %, respectively, due to ion exchange and surface coverage. In samples of the same water quality as Smackover brine, the Li content in the Mg2+-captured material was only 3.20 % of that in directly precipitated Mg(OH)2, due to the adsorption selectivity coefficient of the material for Mg²⁺ to Li⁺ reaching 62.26. The outcomes of this research enlighten the selective capture ability and mechanism of phosphorus atomic sites for Mg2+, providing new insights for efficient Mg/Li separation from salt lakes to improve raw brain grade.

中文翻译：

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自浮核上的磷原子位点对镁离子的特异性捕获促进了盐湖盐水中 Mg/Li 的分离


高效的镁-锂分离是从盐湖盐水中提取锂离子的关键步骤。Mg2+ 从液体沉淀到固体是最简单的分离方法，但析出絮凝物吸附 Li+ 的副反应导致 Mg/Li 分离不完全和锂损失。在这项研究中，我们将磷原子位点接枝到具有自浮分离能力的二氧化硅基原子核上，以制备对 Mg2+ 具有特异性捕获能力的吸附剂，实现从盐水中高效分离 Mg/Li。表面成分分析表明，P 元素含量为 0.99 %，在室温下贡献了 82.20 mg g⁻1 的 Mg2+ 吸附容量。在此过程中，由于离子交换和表面覆盖，材料中 Na 和 Ca 元素的含量分别降低了 1.47 % 和 0.85 %。在与 Smackover 盐水水质相同的样品中，由于 Mg²⁺ 对 Li⁺ 的吸附选择性系数达到 62.26，因此 Mg2+ 捕获材料中的 Li 含量仅为直接沉淀 Mg（OH）2 中的 3.20%。本研究结果揭示了磷原子位点对 Mg2+ 的选择性捕获能力和机制，为从盐湖中高效分离 Mg/Li 以提高生脑等级提供了新的见解。