Hydroxyl-Incorporated Microporous Polymer Comprising 3D Triptycene for Selective Capture of CO<sub>2</sub> over N<sub>2</sub> and CH<sub>4</sub>
Mosim Ansari, Aamir Hanif, Mahmoud M. Abdelnaby, Aasif Helal, Mohd Yusuf Khan
Abstract
High Resolution Image Download MS PowerPoint Slide The rising CO 2 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 2, although they have drawbacks, such as degradation, corrosion, and high regeneration energy requirements. Physical adsorption of CO 2 utilizing microporous adsorbents is a viable alternative that offers excellent efficiency and selectivity for CO 2 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 (% V mic = 70%), a larger BET-specific surface area (SA BET ) of 838 m 2 g –1, and good thermal stability ( T d = 372 °C and char yield > 60%) which makes it a promising adsorbent for CO 2 capture. A strong affinity for CO 2 was shown by TBPP-OH with Q st of 32.9 kJ/mol demonstrating a superior CO 2 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 2 over N 2 and CH 4 for the polymer TBPP-OH were also estimated to be reasonably high indicating good potential for CO 2 separation in different applications. The mechanism of CO 2 adsorption was investigated by using Langmuir and dual-site Langmuir models.