In this work, we investigate the extraction of Li from solutions containing Li and Mg using metal-organic framework (MOF) membranes through molecular dynamics simulations (MD). Five MOFs with different pore sizes are studied. It is found that there is a critical pressure for MOFs with pore size smaller than 7.08 Å, below which Li can be completely separated from Mg. This critical pressure increases as the pore size decreases. Under practical pressures (<50 MPa), MOFs with pore size around 6.5–7.0 Å are optimal for complete separation of Li and Mg. If high pressures can be reached, MOF with pore size of 5.48 Å appears to perform better because it ensures not only perfect separation but also a high flux of Li. The hydration energy, potential of mean force, and density distribution of Li and Mg are computed to explain the separation mechanisms.

中文翻译：

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使用金属有机框架进行 Li+/Mg2+ 分离的分子动力学模拟

在这项工作中，我们通过分子动力学模拟（MD）研究了使用金属有机骨架（MOF）膜从含有锂和镁的溶液中提取锂。研究了五种不同孔径的 MOF。研究发现，孔径小于7.08 Å的MOFs存在一个临界压力，低于该压力，Li可以与Mg完全分离。该临界压力随着孔径减小而增大。在实际压力（<50 MPa）下，孔径约为 6.5-7.0 Å 的 MOF 最适合完全分离 Li 和 Mg。如果可以达到高压，孔径为 5.48 Å 的 MOF 似乎表现更好，因为它不仅能确保完美分离，还能确保高锂通量。计算了 Li 和 Mg 的水合能、平均力势和密度分布，以解释分离机制。