Cost-Effective Zinc-Based Metal–Organic Framework for Highly Efficient Methane Purification

The separation of methane from natural gas poses a significant and crucial challenge in the industry. Currently, the capture of CH 4 from natural gas is dominated by distillation, which is an energy consuming process. Here, we present CALF-20, a metal–organic framework with a three-dimensional pore structure, for separating C 2 H 6 /CH 4 and CH 4 /N 2 mixtures. Interestingly, CALF-20 shows a satisfactory CH 4 uptake of 1.11 mmol/g and C 2 H 6 /CH 4 selectivity of 22.7 (298 K, 100 kPa). CH 4 /N 2 selectivity on CALF-20 at 0.5 kPa reaches 15.0. In addition, breakthrough experiments demonstrated that CALF-20 could effectively separate CH 4 /N 2 and C 2 H 6 /CH 4 mixtures. Molecular simulations highlight the crucial role of strong C–H···N and C–H···π interactions between adsorbates and the CALF-20 framework in achieving the highly selective separation of CH 4 /N 2 and C 2 H 6 /CH 4 mixtures. CALF-20 exhibits superior persistent reusability, outstanding water and moisture stability, and low ligand cost ($53/kg). This study demonstrates CALF-20 as a highly promising material for industrially separating CH 4 /N 2 and C 2 H 6 /CH 4 mixtures.