The removal of carbon dioxide (CO2) from acetylene (C2H2) production is critical yet difficult due to their similar physicochemical properties. Despite extensive research has been conducted on metal-organic frameworks (MOFs) for C2H2/CO2 separation, approaches to designing functionalized MOFs remain limited. Enhancing gas adsorption through simple pore modification holds great promise in molecular recognition and industrial separation processes. This study proposes a guest cation functionalization strategy using the anionic framework SU-102 as the prototype material. Specifically, the guest cation Li+ is introduced into the skeleton by ion exchange to obtain SU-102-Li+. This strategy generates strong interactions between Li+ and gas molecules, thereby elevating C2H2 uptake to 49.18 cm3 g-1 and CO2 uptake to 29.88 cm3 g-1, marking 20.3% and 36.9% improvements over the parent material, respectively. In addition, ideal adsorbed solution theory selectivity calculations and dynamic breakthrough experiments confirmed the superior and stable separation performance of SU-102-Li+ for C2H2/CO2 (25 min g-1) and C2H2 productivity (1.55 mmol g-1). Theoretical calculations further reveals the unique molecular recognition mechanism between gas molecules and guest cations.
Keywords: acetylene/carbon dioxide separation; gas separation; guest cations; guest‐functionalized MOFs; mental organic frameworks (MOFs).
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