Different types of amine-functionalized MOF structures were analyzed in this work using molecular simulations in order to determine their potential for post-combustion carbon dioxide capture and separation. Six amine models -of different chain lengths and degree of substitution- grafted to the unsaturated metal sites of the M₂(dobdc) MOF [and its expanded version, M₂(dobpdc)] were evaluated, in terms of adsorption isotherms, selectivity, cyclic working capacity and regenerability. Good agreement between simulation results and available experimental data was obtained. Moreover, results show two potential structures with high cyclic working capacities if used for Temperature Swing Adsorption processes: mmen/Mg/DOBPDC and mda-Zn/DOBPDC. Among them, the -mmen functionalized structure has higher CO₂ uptake and better cyclability (regenerability) for the flue gas mixtures and conditions studied. Furthermore, it is shown that more amine functional groups grafted on the MOFs and/or full functionalization of the metal centers do not lead to better CO₂ separation capabilities due to steric hindrances. In addition, multiple alkyl groups bonded to the amino group yield a shift in the step-like adsorption isotherms in the larger pore structures, at a given temperature. Our calculations shed light on how functionalization can enhance gas adsorption via the cooperative chemi-physisorption mechanism of these materials, and how the materials can be tuned for desired adsorption characteristics.

在这项工作中，使用分子模拟分析了不同类型的胺官能化MOF结构，以确定它们在燃烧后二氧化碳捕获和分离中的潜力。六个胺模型-不同的链长和取代度-接枝到M ₂（dobdc）MOF的不饱和金属位点[及其扩展版本M ₂（dobpdc）]在吸附等温线，选择性，循环工作能力和可再生性方面进行了评估。仿真结果与可用的实验数据之间取得了很好的一致性。此外，结果表明，如果用于变温吸附工艺，则具有两个具有高循环工作能力的潜在结构：mmen / Mg / DOBPDC和mda-Zn / DOBPDC。其中，-mmen功能化结构对烟气混合物和所研究的条件具有更高的CO ₂吸收率和更好的循环性（可再生性）。此外，表明在MOF上接枝更多的胺官能团和/或金属中心的完全官能化不会导致更好的CO _2。由于位阻而具有的分离能力。另外，在给定温度下，与氨基键合的多个烷基在较大的孔结构中产生阶梯状吸附等温线的偏移。我们的计算揭示了官能化如何增强气体吸附通过 这些材料的协同化学-物理吸附机理，以及如何调整材料以获得所需的吸附特性。