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.