High-Throughput Screening of Anion-Pillared Metal–Organic Frameworks for the Separation of Light Hydrocarbons

Separation
of light hydrocarbons is a challenging and energy-intensive
industrial process. Adsorptive separations using metal–organic
frameworks (MOFs) have drawn attention because they offer a potential
route to higher energy efficiency for these separations. In this work,
we performed high-throughput screening for the separations of C1–C3 light hydrocarbons based on adsorption
in our previously reported anion-pillared MOF database. We explored
the relationships of selectivity in the dilute limit with physical
parameters including the largest cavity diameter, surface area, and
pore volume fraction of MOFs. On the basis of this screening, we assessed
the selective adsorption of binary light hydrocarbon mixtures for
some promising MOFs by GCMC simulations and compared the selectivities
with those of previously reported sorbent materials. We observed a
trade-off between two performance metrics in which MOFs with higher
selectivity usually show lower working capacity. When the pore space
is available to both components, the vdW interaction plays a dominant
role in light hydrocarbon separations. However, if the pore sizes
are too small, separation is possible based on molecular sieving.
The comparisons with some reported porous materials indicate that
SIFSIX-2-Ni-i, SIFSIX-6-Cd-i, InFFIVE-5-Zn-i, and GaFFIVE-5-Cd-i appear
promising for C3H6/C3H8, C2H6/CH4, C3H6/C2H4, and C3H8/C2H4 separations, respectively.