Hydrophobic metal-organic framework Featuring multiple O/S active sites for efficient CH4/N2 separation under humid conditions

The enrichment of low-concentration coal-bed methane is beneficial to solving the world’s energy concerns. However, most adsorbents used for CH 4 /N 2 separation from coal-bed methane are hydrophilic and ineffective under humid conditions. In this study, a hydrophobic nickel-based metal–organic framework (TUTQ-1Ni) was developed for efficient CH 4 /N 2 separation under humid conditions. Adsorption results show that, at 298 K and 1 bar, TUTQ-1Ni exhibits the highest CH 4 /N 2 selectivity (11.0) among the reported hydrophobic CH 4 -selective metal–organic frameworks. The results of theoretical calculations reveal that multiple O/S sites provide strong adsorption affinity for CH 4 over N 2 . Further, breakthrough experiments confirm the suitability of the material for CH 4 /N 2 separation, with the separation performance being maintained at even a high relative humidity of 100 %. The pressure swing adsorption simulation results indicate that TUTQ-1Ni is a potential candidate material for the selective capture of methane from coal-bed methane.