Hydroxyl-Incorporated Microporous Polymer Comprising 3D Triptycene for Selective Capture of CO over N and CH

The rising CO concentration in the atmosphere contributes significantly to global warming, necessitating effective carbon capture techniques. Amine-based solvents are widely employed for the chemisorption of CO, although they have drawbacks, such as degradation, corrosion, and high regeneration energy requirements. Physical adsorption of CO utilizing microporous adsorbents is a viable alternative that offers excellent efficiency and selectivity for CO capture. This work presents the facile one-pot synthesis of a 3D-triptycene-containing hyper-cross-linked microporous polymer (TBPP-OH) possessing hydroxyl groups. The presence of triptycene units in the TBPP-OH polymeric structure gives several desirable features, such as inherent microporosity, larger surface area, and improved thermal stability. TBPP-OH showed considerable microporosity (% = 70%), a larger BET-specific surface area (SA) of 838 m g, and good thermal stability ( = 372 °C and char yield > 60%) which makes it a promising adsorbent for CO capture. A strong affinity for CO was shown by TBPP-OH with of 32.9 kJ/mol demonstrating a superior CO adsorption capacity of 2.77 mmol/g at 273 K and 1 bar pressure where the volume of the micropore plays a significant role. The selectivity values of CO over N and CH for the polymer TBPP-OH were also estimated to be reasonably high indicating good potential for CO separation in different applications. The mechanism of CO adsorption was investigated by using Langmuir and dual-site Langmuir models.