Effect of the structural constituents of metal organic frameworks on carbon dioxide capture

• CO2 capture by MOFs largely depends on their metal and organic ligand constituents.
• Polar and amine groups tend to be the most effective functional groups for capture.
• Synthetic routes of MOFs affect their crystal morphology and CO2 capture property.
• MOFs in mixed matrix membranes offer effective diffusion channels with selectivity.

Currently one of the heightened global concerns is increasing CO2 atmospheric concentration which is argued to be one the main contributing factors in rising global temperature and climate change. Carbon capture and storage technologies show promise in this field with most of the research currently focused on large CO2 emission sources such as coal fired power plants. Competitive CO2 capture capacities were obtained with metal organic frameworks (MOFs), an emerging class of crystalline materials, as adsorbents at the CO2 partial pressures expected in flue gas or lower, owing to their unique properties including high surface area, well-defined porosity, and ease of chemical tunability of the framework structure for introduction of additional physical and/or chemical properties. This review paper summarizes the recent and notable works in the area of CO2 capture using MOFs as adsorbents with an emphasis on their structure–property-relationship, i.e., structural variations of MOF frameworks and their consequences to CO2 capture performance. Structures of the MOFs reported are discussed and compared based on the effects of the choice for the main constituting parts such as metal centers and organic ligands. Effect of addition of functional groups have been found to be significant over the years and also discussed here. Various synthesis routes to achieve MOF crystals, and the role of MOFs particles within mixed matrix membranes for CO2 separation are also examined. Lastly, an economic analysis of MOF synthesis techniques and implementation are discussed.

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