Decoding the zeolite cage effect in one-step ethylene purification from CO₂/C₂H₂/C₂H₄ mixtures

Utilizing physical adsorption for ethylene purification from complex mixtures can significantly reduce the energy cost for production. The purification of multi-component systems through a single adsorption process presents a considerable challenge, largely stemming from the absence of customized strategies and thorough investigations into adsorption behaviours. We aim to understand adsorbents through a unique cage recognition approach and leverage these insights to develop an effective purification adsorbent, with the successful synthesis of SSZ-16 zeolite meeting requirements for multi-component purification. This zeolite, featuring a long aft supercage and a narrow gme cage construct two adsorption cages. The dense π-electron cloud of C₂H₂ enables a stronger interaction in aft cage, while CO₂ is selectively captured within the environmentally compatible gme cage, demonstrating significantly higher C₂H₂ and CO₂ adsorption capacity. The separation experiments reveal that SSZ-16 exhibits exceptional performance, with an unprecedented polymer-grade C₂H₄ productivity of 2099.16 L/kg from the CO₂/C₂H₂/C₂H₄ mixture.