One-step purification of ethylene from acetylene and carbon dioxide by ultramicroporous carbons

The one-step adsorptive separation of high-purity ethylene (C 2 H 4 ) from a ternary gas mixture (C 2 H 2 /C 2 H 4 /CO 2 ) is challenging and has not been reported on porous carbons. Herein, we report camphor seeds husk-derived ultramicroporous carbons (CSHs) show high affinities toward acetylene (C 2 H 2 ) and carbon dioxide (CO 2 ) over C 2 H 4 . The optimized CSH-2-700 with high heteroatom contents and centered pore size distributions shows high C 2 H 2 adsorption capacity (2.24 mmol g −1 ) and record ideal adsorbed solution theory (IAST) C 2 H 2 /C 2 H 4 selectivity (10.2) among one-step C 2 H 4 purification adsorbents. Meanwhile, CSH carbons are the only carbon adsorbents that preferentially adsorb CO 2 over C 2 H 4 , with a CO 2 /C 2 H 4 selectivity of 1.9 under ambient conditions. Furthermore, dynamic breakthrough experiments verified its feasibility for one-step C 2 H 4 purification from a three-component C 2 H 2 /C 2 H 4 /CO 2 gas-mixture.