Triphenylene-based porous polymer for selective CO₂ capture with molecular modeling insights and CO₂/N₂ separation performance indicators for vacuum swing adsorption

Rising atmospheric CO₂ levels are a major driver of global warming, highlighting the need for effective capture technologies. Although alkanolamine-based scrubbing solutions are extensively applied for CO₂ chemisorption, their use is hindered by challenges including degradation, corrosion, and substantial energy requirements for regeneration. Alternatively, physical adsorption using microporous adsorbents emerges as a promising strategy, delivering both high capture efficiency and selectivity. In this work, a triphenylene-based porous polymer (TP-POP) was prepared by one-pot Friedel-Crafts reaction, yielding a highly microporous network (pore size = 1.2 nm, SA_BET = 778 m² g⁻¹) with high thermal stability (T_d > 160 °C). The multiple arene rings of triphenylene and its tailored microporosity conferred CO₂ affinity (Q_st = 28.7 kJ mol⁻¹), indicating a physisorption mechanism. TP-POP exhibited high adsorption capacity up to 3.40 mmol g⁻¹ and CO₂ over N₂ selectivity (37 and 42 at 273 and 298 K, respectively). Furthermore, the CO₂ adsorption on TP-POP was investigated through Grand Canonical Monte Carlo (GCMC) simulation. This study further presents a comprehensive evaluation of critical performance metrics for a cyclic Vacuum Swing Adsorption (VSA) technique, enabling an assessment of TP-POP's practical suitability for CO₂ separation. TP-POP demonstrates promising working capacity up to 2.35 mmol g⁻¹ and high CO₂ purity in the desorbed stream (>92 % at 298 K), and good regenerability (78.8 % at 298 K). These results highlight TP-POP's balanced performance in capacity, selectivity, regenerability, and purity, rendering it a potential porous material for VSA-based CO₂ separation.