Highly Selective Ethylene/Ethane Separation in MOF Composites through Pore Contraction and Particle Size Enlargement Strategy

Abstract The discrimination of ethylene (C 2 H 4 ) and ethane (C 2 H 6 ) by the precise regulation of porous materials is important and challenging. In this work, the quasi‐exclusion of C 2 H 6 from C 2 H 4 is realized through a facile polymer modification and shaping method of metal–organic framework ZnAtzPO 4 (Atz = 3‐amino‐1,2,4‐triazole). The polymer (carboxymethyl cellulose, CMC) modification and shaping of ZnAtzPO 4 @CMC result in pore contraction and particle size enlargement, which impedes the diffusion of larger C 2 H 6 molecules and improves the kinetic separation of C 2 H 4 /C 2 H 6 . The C 2 H 6 capacity decreases steeply from 1.63 (ZnAtzPO 4 powder) to 0.27 mmol g −1 (ZnAtzPO 4 @CMC), and the resulting C 2 H 4 /C 2 H 6 uptake ratio increases from 1.38 to 6.67. Kinetic adsorption experiments confirm that ZnAtzPO 4 @CMC presents a negligible C 2 H 6 dynamic capacity and the diffusion difference between C 2 H 4 and C 2 H 6 is amplified significantly. The corresponding kinetic C 2 H 4 /C 2 H 6 separation selectivity of ZnAtzPO 4 @CMC increases from 13.06 (ZnAtzPO 4 ) to 34.67, superior to the most reported benchmark materials. Furthermore, ZnAtzPO 4 @CMC exhibits excellent breakthrough performance for equimolar C 2 H 4 /C 2 H 6 mixture separation. This study provides guidance to discriminate similar gases through polymer modification of MOFs.