Scalable Room-Temperature Synthesis of Highly Robust Ethane-Selective Metal–Organic Frameworks for Efficient Ethylene Purification

The
development of new techniques and materials that can separate
ethylene from ethane is highly relevant in modern applications. Although
adsorption-based separation techniques using metal–organic
frameworks (MOFs) have gained increasing attention, the relatively
low stability (especially water resistance) and unscalable synthesis
of MOFs severely limit their application in real industrial scenarios.
Addressing these challenges, we rationally designed and synthesized
two new C2H6-selective MOF adsorbents (NKMOF-8-Br and -Me) with ultrahigh chemical and
thermal stability, including water resistance. Attributed to the nonpolar/hydrophobic
pore environments and appropriate pore apertures, the MOFs can capture
C2 hydrocarbon gases at ambient conditions even in high humidity.
The single-crystal structures of gas@NKMOF-8 realized
the direct visualization of adsorption sites of the gases. Both the
single-crystal data and simulated data elucidate the mechanism of
selective adsorption. Moreover, the NKMOF-8 possesses
high C2H6 adsorption capacity and high selectivity,
allowing for efficient C2H6/C2H4 separation, as verified by experimental breakthrough tests.
Most importantly, NKMOF-8-Br and -Me can
be scalably synthesized through stirring at room temperature in minutes,
which confers them with great potential for industrial application.
This work offers new adsorbents that can address major chemical industrial
challenges and provides an in-depth understanding of the gas binding
sites in a visual manner.