Enhanced ion-induced SO2 capture via surface electric field engineering in cage-like organic network

Selective capture of sulfur dioxide (SO 2 ) is of great significance in the context of environmental protection, yet it remains an ongoing challenge. To address inefficient SO 2 removal from flue gas, this study synthesized a cage-like organic network (CON) and converted it into an ionic I-CON via facile quaternization modification. Solid-state 13 C NMR, XPS, SEM and TEM-EDS confirmed iodine ion (I − ) incorporation in I-CON, narrowing its pore size to 1.05 nm. Single-component gas adsorption experiments demonstrated that I-CON exhibits an SO 2 uptake as high as 16.44 mmol/g at 298 K, surpassing that of CON (11.54 mmol/g). Furthermore, the IAST (Ideal Adsorbed Solution Theory) selectivity of I-CON for SO 2 /CO 2 binary gas mixture also exceeded that of CON (112.10 vs 93.96). Dynamic tests showed I-CON has prolonged SO 2 breakthrough time to 3592 s, indicating that the high dynamic selectivity of I-CON for SO 2 /CO 2 and SO 2 /N 2 . DFT calculations revealed that the synergistic effect between the surface electric field-mediated induced polarization and charge transfer in I-CON significantly enhances its selective adsorption performance toward SO 2 . This study validates the potential of I-CON in the efficient capture of SO 2 .