Carbon dioxide capture from processes is one of the strategies adopted to decrease anthropogenic greenhouse gas emissions. To lower the cost associated with the regeneration of amine-based scrubber systems, one of the envisaged strategies is the grafting of amines onto high-surface-area supports and, in particular, onto metal-organic frameworks (MOFs). In this study, the interaction between CO2 and aliphatic and aromatic amines has been characterized by quantum mechanical methods (MP2), focusing attention both on species already reported in MOFs and on new amine-based linkers, to inspire the rational synthesis of new high-capacity MOFs. The calculations highlight binding-site requisites and indicate that CO2 vibrations are independent of the adsorption energy and monitoring them in probe-molecule experiments is not a suitable marker of efficient adsorption. Scrubbed away: Quantum mechanics is used as a screening tool to investigate the affinity of different functional groups towards CO2. The calculations explain the large CO2 affinity observed experimentally for 2-amino-1,4-benzenedicarboxylate-based materials by the presence of pairs of -NH2 groups and not by the direct interaction with isolated -NH2 groups (see picture).
- carbon dioxide fixation
- density functional calculations
- metal-organic frameworks
- supercritical fluids