Pore surface fluorination and PDMS deposition within commercially viable metal-organic framework for efficient C2H2/CO2 separation

Removing CO 2 impurities from C 2 H 2 /CO 2 mixtures is an essential process for producing high-purity C 2 H 2 under high humidity. High-stability and low-cost metal-organic frameworks (MOFs) have great potential in C 2 H 2 /CO 2 industrial separation. However, due to the complementary adsorption of H 2 O and CO 2 , water vapor has a negative impact on the implementation of C 2 H 2 purification. Herein, we propose a synergistic strategy of pore surface functionalization and polydimethylsiloxane (PDMS) deposition to avoid the influence of water vapor while improving C 2 H 2 /CO 2 separation performance. A commercially available metal-organic framework (ALP-MOF-1) was used as a template to functionalize its pore surface with CH 3 , Br, and F. The optimized material ALP-MOF-1(F) exhibits the highest C 2 H 2 uptake (117.78 cm 3 /g at 298 K and 10 6 Pa) and C 2 H 2 /CO 2 uptake ratio (3.1) among ALP-MOF systems. Computational simulations show that the well-matched pore space and the significant electronegativity and polarizability of the fluorine groups on the pore surface jointly enhance the framework-C 2 H 2 interaction. Furthermore, the deposition of PDMS on ALP-MOF-1 and ALP-MOF-1(F) significantly improves their C 2 H 2 /CO 2 separation stability under 80% humidity conditions.