Design of a nitrogen-rich perylene-triazine porous organic polymer for iodine and CO2 adsorption

Abstract

Porous organic polymers (POPs) have emerged as promising materials for environmental remediation owing to their high surface area, structural tunability, and chemical stability. In this work, we present a nitrogen-rich POP named PYTP, synthesized via a solvent-assisted polycondensation process from triazine, perylene, and pyridine-based polymeric building blocks. The resulting polymer features a nitrogen-rich conjugated framework and was obtained in high yield using a simple, scalable method. Structural characterization through FT-IR, solid-state ¹³C CP-MAS NMR, and FE-SEM confirmed the successful formation and stability of the PYTP framework. BET surface area analysis revealed a specific surface area of 135 m² g⁻¹ and an average pore size of 1.2 nm, indicating a microporous nature favourable for gas uptake. The PYTP polymer exhibited outstanding performance in iodine capture, with a vapor adsorption capacity of 355 wt% and 97% removal efficiency from hexane solution. Elemental mapping confirmed the presence of iodine, and recyclability tests demonstrated excellent reusability over multiple cycles in both vapor and solution phases. Significantly, PYTP also achieved high removal efficiency of crude iodine under real-time conditions, highlighting its applicability for practical environmental remediation scenarios. Furthermore, CO₂ adsorption studies showed a maximum uptake of ∼50 cc g⁻¹ (9.81 mg g⁻¹), indicating good CO₂ uptake capacity with no additional adsorption beyond P/P₀ ≈ 0.9. This behaviour reflects efficient pore filling and strong CO₂–framework interactions. These findings underscore PYTP as a highly effective, reusable, and dual-functional adsorbent with strong potential for real-time radioactive iodine removal, carbon capture, and broader nuclear waste management applications.