Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
Phys Chem Chem Phys. 2013 Jun 21;15(23):9093-106. doi: 10.1039/c3cp50774b. Epub 2013 May 3.
The adsorption of noble gases and nitrogen by sixteen metal-organic frameworks (MOFs) was investigated using grand canonical Monte Carlo simulation. The MOFs were chosen to represent a variety of net topologies, pore dimensions, and metal centers. Three commercially available MOFs (HKUST-1, AlMIL-53, and ZIF-8) and PCN-14 were also included for comparison. Experimental adsorption isotherms, obtained from volumetric and gravimetric methods, were used to compare krypton, argon, and nitrogen uptake with the simulation results. Simulated trends in gas adsorption and predicted selectivities among the commercially available MOFs are in good agreement with experiment. In the low pressure regime, the expected trend of increasing adsorption with increasing noble gas polarizabilty is seen. For each noble gas, low pressure adsorption correlates with several MOF properties, including free volume, topology, and metal center. Additionally, a strong correlation exists between the Henry's constant and the isosteric heat of adsorption for all gases and MOFs considered. Finally, we note that the simulated and experimental gas selectivities demonstrated by this small set of MOFs show improved performance compared to similar values reported for zeolites.
使用巨正则蒙特卡罗模拟研究了 16 种金属有机骨架（MOF）对稀有气体和氮气的吸附。选择这些 MOF 代表了各种净拓扑、孔径和金属中心。还包括三种市售的 MOF（HKUST-1、AlMIL-53 和 ZIF-8）和 PCN-14 进行比较。使用体积法和重量法获得的实验吸附等温线用于比较模拟结果与氪、氩和氮气的吸收。气体吸附的模拟趋势和市售 MOF 之间的预测选择性与实验结果吻合良好。在低压区，观察到随着稀有气体极化率的增加吸附增加的预期趋势。对于每种稀有气体，低压吸附与几个 MOF 特性相关，包括自由体积、拓扑和金属中心。此外，所有气体和考虑的 MOF 的亨利常数与等吸附热之间存在很强的相关性。最后，我们注意到，与沸石报道的类似值相比，这一小组 MOF 表现出的模拟和实验气体选择性具有更好的性能。
