Storage and Separation of Carbon Dioxide and Methane in Hydrated Covalent Organic Frameworks

Storage and separation of carbon dioxide and methane and their mixtures are important processes for environmental and energetic reasons. We study these processes using hydrated nanoporous materials and explore the use of solvents as alternative to improve the performance of these materials. We used boronate ester covalent organic frameworks (COF-5,-6,-10, and-102) because of their stability upon water. The best separation for hydrated structure is obtained with COF-102. However, the improvement on the separation performance requires a high percentage of hydration, reducing the capacity of the structure. To overcome this limitation, we suggest to introduce room-temperature ionic liquid as a solvent. Our simulations show that the use of small amounts of ionic liquids in the structure leads to higher values of adsorption selectivity than the use of hydrated structures.