Modulating Adsorption Kinetics in a 3D-Interconnected Nanocavity Framework with Narrow Apertures for Enhanced...

Area of Science:

• Materials Science
• Chemical Engineering
• Separation Science

Background:

• Propylene/propane (C3H6/C3H8) separation is energy-intensive due to small boiling point differences.
• Existing porous materials struggle with adsorption capacity, selectivity, and kinetics trade-offs for this separation.
• Novel materials are needed to improve the efficiency and sustainability of C3H6/C3H8 separation.

Purpose of the Study:

• To synthesize and characterize a novel metal-organic framework (MOF) for efficient C3H6/C3H8 separation.
• To investigate the adsorption capacity, selectivity, and kinetics of the MOF for C3H6 and C3H8.
• To elucidate the host-guest interactions and pore structure effects on separation performance.

Main Methods:

• Synthesis and characterization of the NiPz4Bim metal-organic framework.
• Gas adsorption isotherms at 298 K and 1 bar for C3H6 and C3H8.
• Kinetic uptake analysis using effective diffusion coefficients.
• Neutron powder diffraction, Monte Carlo simulations, and DFT calculations.

Main Results:

• NiPz4Bim exhibits selective adsorption with capacities of 3.24 mmol/g for C3H6 and 2.74 mmol/g for C3H8.
• High kinetic selectivity (51.96) due to enhanced C3H6 diffusion through narrow apertures (~5 Å).
• Pore geometry facilitates selective van der Waals and π-π interactions with C3H6.
• Demonstrated high stability and reusability over multiple cycles.

Conclusions:

• NiPz4Bim offers an efficient and stable adsorbent for C3H6/C3H8 separation, overcoming limitations of traditional methods.
• Pore-geometry engineering is crucial for designing MOFs for separating structurally similar molecules.
• This MOF has significant implications for sustainable olefin production.