Molecular dynamics simulations of Li+/Mg2+ separation using metal-organic frameworks

In this work, we investigate the extraction of Li + from solutions containing Li (+) and Mg (2+) 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 & Aring;, below which Li + can be completely separated from Mg 2+ . This critical pressure increases as the pore size decreases. Under practical pressures ( <50 MPa), MOFs with pore size around 6.5 - 7.0 & Aring; are optimal for complete separation of Li + and Mg (2+) . If high pressures can be reached, MOF with pore size of 5.48 & Aring; 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 2+ are computed to explain the separation mechanisms.