Cost-Effective Synthesis of Carbazole-Based Nanoporous Organic Polymers for SO₂ Capture

Sulfur dioxide (SO₂), a pervasive air pollutant, poses significant environmental and health risks, necessitating advanced materials for its efficient capture. Nanoporous organic polymers (NOPs) have emerged as promising candidates; however, their development is often hindered by high synthesis temperatures, complex precursors, and limited SO₂ selectivity. Herein, we report a room-temperature, cost-effective synthesis of carbazole-based nanoporous organic polymers (CNOPs) using 1,3,5-trioxane and paraldehyde, offering a significant advancement over traditional Friedel-Crafts alkylation methods. The resulting CNOPs exhibit a high surface area of up to 842 m²·g^-1 and feature ultramicroporous structures optimized for SO₂ adsorption. At 298 K and 1 bar, the CNOPs demonstrated SO₂ adsorption capacities of up to 9.39 mmol·g^-1. Ideal adsorbed solution theory (IAST) calculations revealed outstanding selectivities of 105 for SO₂/CO₂ and 6139 for SO₂/N₂ mixtures, supported by breakthrough experiments demonstrating superior separation performance. This work not only provides a straightforward synthetic route for CNOPs but also offers valuable insights into the design and development of porous materials tailored for enhanced SO₂ capture, addressing critical environmental and health challenges.