Microporous MOF for simultaneous high thermodynamic and kinetic synergistic separation of propylene and propane.

Abstract

Efficient separation of propylene from propane is a critical yet challenging industrial process. While rigid molecular sieves offer ideal selectivity, their narrow nanopores inherently constrain adsorption capacity and diffusion kinetics due to compromised thermodynamic-kinetic trade-offs. To address this, we report ZSTU-10, a molecular sieve constructed via structure-directing agents. Uniquely, ZSTU-10 features localized sieving gates for selective guest admission, expansive diffusion channels for rapid transport, and central pore cavities for high-capacity storage. This gate-channel-cavity architecture enables the precise exclusion of propane while facilitating the dense packing and fast diffusion of propylene, achieving simultaneous thermodynamic-kinetics optimization in molecular sieving. Static adsorption experiments demonstrate an exceptional propylene uptake (97.7 cm³cm^-3) at 298 K and 1 bar. Time-dependent uptake kinetics revealed a propylene diffusion coefficient (4.29 × 10^-9cm²s^-1) in ZSTU-10 surpassing benchmarks by two orders of magnitude. Dynamic breakthrough experiments demonstrate that ZSTU-10 produces high-purity propylene (99.1%) with a productivity of 37.5 L kg^-1 in a single adsorption-desorption cycle.