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

Abstract

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.