Efficient carbon dioxide capture from flue gas and natural gas by a robust metal–organic framework with record selectivity and excellent granulation performance.

• A stable and cost-effective MOF was prepared for benchmark CO 2 capture. • High CO 2 capacity with record CO 2 /N 2 and CO 2 /CH 4 selectivity was achieved. • Impressive CO 2 capacity of 2.60 mmol/g in CO 2 /N 2 breakthrough experiments. • MOF beads were granulated with high MOF loading and retained separation performance. The design of porous materials for CO 2 capture from flue gas and natural gas is highly demanded. However, it is challenging to target materials that combine high CO 2 capacity and CO 2 selectivity. In this work, we report a robust metal–organic framework (MOF) Zn-ox-mtz with one dimensional channels and narrow windows for excellent CO 2 capture from CO 2 /N 2 (simulated flue gas) and CO 2 /CH 4 (simulated natural gas) with high selectivity. Zn-ox-mtz exhibits a high CO 2 capacity (58.0 STP cm3 g−1 at 15 kPa), excellent CO 2 /N 2 (15/85, S > 106) and CO 2 /CH 4 (50/50, S > 105) selectivity and good chemical stability. In addition, the practical separation performance is demonstrated by breakthrough experiments under various process conditions. A efficient separation is achieved with the impressive CO 2 capacity of 2.60 ± 0.12 mmol g−1 at 298 K. Importantly, the outstanding performance is sustained under high humidity. The molecular sieving mechanism investigated by theoretical calculations indicated that CO 2 with small molecular size is tightly trapped by multiple C = O···H-C hydrogen bonding and O = C···O forces in the cavity while CH 4 and N 2 with larger molecular size display overlarge energy barrier to cross the contract pore windows. Moreover, the granulation of Zn-ox-mtz by hydroxypropyl cellulose is realized with high MOF loading (93.8 %) and the granulated Zn-ox-mtz beads retained the excellent CO 2 /N 2 and CO 2 /CH 4 separation performance. [ABSTRACT FROM AUTHOR]