Triptycene-Based and Keto-Functionalized Porous Organic Polymer for Selective CO₂ Capture over N₂/CH₄ and Iodine Sequestration Applications

A triptycene-based keto-functionalized hyper-cross-linked polymer (Keto-POP) was synthesized using commercially available triptycene (TP) and 1,3,5-benzenetricarbonyl trichloride (BTC) via an AlCl3-catalyzed Friedel–Crafts acylation reaction. Gas sorption studies showed remarkable adsorption capacities, with the Keto-POP exhibiting CO2 uptake of 207.1 mg/g at 273 K and 133.5 mg/g at 298 K, CH4 uptake of 35.4 mg/g at 273 K and 14.4 mg/g at 298 K, and H2 uptake of 20.3 mg/g at 77 K and 1 bar. The material also exhibited impressive selectivity CO2/N2 (74.7) and CO2/CH4 (7.8) at 273 K. In addition to gas adsorption, the Keto-POP exhibited iodine uptake with 105 wt % uptake in the vapor phase at 353 K and 1214 mg/g from aqueous solution at 298 K. Desorption experiments confirmed that iodine can be efficiently released into methanol. The material remained recyclable for at least four cycles with minimal performance degradation, making it suitable for sustainable applications. The ease of synthesis using economical monomers and scalable reaction conditions makes Keto-POP a highly competitive candidate for CO2 capture, CH4 and H2 storage, and iodine sequestration applications.