Biogas, which involves methane as the combustible compound, is an abundant and renewable energy resource that produces less harmful gases than conventional fossil-based liquid and solid energy sources. Although biogas is of primary interest due to its methane content, it may also include other gases, such as CO₂, N₂, H₂S, and NH₃. Studies investigating biogas purification often assume that biogas is a binary 50%/50% mixture of methane and carbon dioxide. However, together with N₂, the toxic contaminants, H₂S and NH₃ should be accounted for in the biogas mixture for a more realistic separation application. In this study, the computation-ready experimental metal–organic framework (CoRE-MOF) database is screened to identify a shortlist of potentially high-performing MOFs for multi-component biogas purification. Our hierarchical screening process involves (i) removal of MOFs with sub-3 Å pore limiting diameter and uncommon metal nodes, (ii) removal of MOFs that do not selectively capture the four undesired compounds, as determined from grand canonical Monte Carlo (GCMC) simulations for the binary mixtures of CH₄/(CO₂ or N₂ or H₂S or NH₃), and (iii) ranking of the remaining structures based on various performance metrics determined from GCMC for a five-component mixture. Finally, the relations between some of these metrics and structural properties are discussed to reveal favorable structural characteristics for biogas upgrading.

中文翻译：

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用于生物气净化的金属有机框架的计算筛选†

沼气涉及甲烷作为可燃化合物，是一种丰富的可再生能源，比传统的基于化石的液体和固体能源产生的有害气体更少。尽管由于沼气的甲烷含量而引起人们的广泛关注，但沼气还可以包括其他气体，例如CO ₂，N ₂，H ₂ S和NH ₃。研究沼气净化的研究通常假设沼气是甲烷和二氧化碳的50％/ 50％二元混合物。但是，与N ₂一起，有毒污染物H ₂ S和NH ₃在沼气混合物中应考虑到更现实的分离应用。在本研究中，筛选了可计算的实验性金属-有机框架（CoRE-MOF）数据库，以识别出用于多组分沼气净化的潜在高性能MOF的候选清单。我们的分级筛选过程涉及（i）去除孔径小于3Å且金属节点不常见的MOF，（ii）去除无法选择性捕获四种不希望有的化合物的MOF，这是根据经典的蒙特卡洛（GCMC）方法确定的CH ₄ /（CO ₂或N ₂或H ₂ S或NH ₃的二元混合物的模拟），以及（iii）根据GCMC针对五组分混合物确定的各种性能指标对其余结构进行排名。最后，讨论了其中一些指标与结构特性之间的关系，以揭示有利于沼气升级的结构特性。