Inverse CO2/C2H2 separation in a pillared-layer framework featuring a chlorine-modified channel by quadrupole-moment sieving

Abstract

• A MOF with plentiful Cl atoms hanging on the pore surface was successfully built. • The inverse CO 2 /C 2 H 2 separation was achieved by inserting Cl atoms in the MOF. • Impact of Cl atoms toward adsorb CO 2 and C 2 H 2 is evidenced by simulations. Selective isolation of CO 2 from C 2 H 2 using CO 2 -selective adsorbent is a huge challenge due to their analogous physical properties as well as molecular sizes and shapes. In this work, utilizing an effective strategy of embedding electronegative Cl atoms in pore surface of MOF, a 3D pillared-layer ultramicroporous MOF, [Zn(atz)(BDC-Cl4) 0.5 ] n (1) (Hatz = 3-amino-1,2,4-triazole; BDC-Cl4 = tetrachloroterephthalic acid) for inverse CO 2 /C 2 H 2 separation was successfully constructed. This MOF show a CO 2 /C 2 H 2 (V:V = 1:1) adsorption selectivity of 2.4 at 285 K and 100 kPa. Computational studies further uncover CO 2 recognition mechanism is due to the matching of the unique pore environment decorating by Cl atoms with quadrupole moment of CO 2 .