Interpenetrated Zirconium–Organic Frameworks: Small Cavities versus Functionalization for CO₂ Capture

Porous interpenetrated zirconium–organic frameworks (PIZOFs) with various functional groups are explored for CO₂ capture using molecular simulation and experiment. Functionalization enhances the CO₂ uptake and selectivity over other gases, but small cavities play an even more important role. Particularly at low pressures, small cavities enhance the CO₂ adsorption density nearly 5 times greater than the functionalization. PIZOF-2 outperforms the other PIZOF structures for CO₂ separation from methane and nitrogen (related to raw natural gas and postcombustion of coal mixtures) due to the combination of small cavities around 5 Å in diameter and functionalized linkers with methoxy groups attached to the central ligand. The small cavities within the interpenetrated structures are crucial for achieving high selectivities, especially for cavities surrounded by a combination of 6 benzene rings, 2 metal clusters, and 4 methoxy groups that offer a tight overlapping potential energy field, ideal for “catching” CO₂

Interpenetrated Zirconium–Organic Frameworks: Small Cavities versus Functionalization for CO₂ Capture

Porous interpenetrated zirconium–organic frameworks (PIZOFs) with various functional groups are explored for CO₂ capture using molecular simulation and experiment. Functionalization enhances the CO₂ uptake and selectivity over other gases, but small cavities play an even more important role. Particularly at low pressures, small cavities enhance the CO₂ adsorption density nearly 5 times greater than the functionalization. PIZOF-2 outperforms the other PIZOF structures for CO₂ separation from methane and nitrogen (related to raw natural gas and postcombustion of coal mixtures) due to the combination of small cavities around 5 Å in diameter and functionalized linkers with methoxy groups attached to the central ligand. The small cavities within the interpenetrated structures are crucial for achieving high selectivities, especially for cavities surrounded by a combination of 6 benzene rings, 2 metal clusters, and 4 methoxy groups that offer a tight overlapping potential energy field, ideal for “catching” CO₂

Magnetic Framework Composites for Low Concentration Methane Capture

This study proposes a simple and energy efficient technique for methane (CH₄) capture from low concentration emission sources. An extrusion-based process was used to fabricate magnetic framework composites (MFCs) from a metal organic framework (MOF), aluminum fumarate, and MgFe₂O₄ magnetic nanoparticles (MNP). Methane uptake for MFCs with different MNP loading at 1 bar and 300 K revealed a high methane uptake of up to 18.2 cm³ g^–1. To regenerate the MFCs, a magnetic induction swing adsorption (MISA) process was applied. A working capacity of 100% was achieved for the MFC over 10 adsorption–desorption cycles with an average of 6 min per cycle for the regeneration step. The ability to access 100% of the adsorbed CH₄ in the MFC with rapid and localized heating achieved with the MISA process potentially provides an energy efficient technique for CH₄ capture and reuse from low concentration sources