Highly Selective Capture of Low-Concentration Sulfur Dioxide in Hydroxyl-Functionalized Ionic Microporous Polymers through Multiple Interactions

Abstract

Developing porous organic polymers (POPs) simultaneously exhibiting high selectivity and capacity for the efficient removal of low-concentration SO2 is of great significance but challenging. In this study, a novel class of hydroxyl-functionalized ionic microporous polymers was prepared via a phenol-formaldehyde condensation reaction based on branched ionic monomers and phloroglucinol, which not only features dual functionality combining abundant ionic content with high-density hydroxyl groups but also affords a well-developed ultramicroporous structure. Benefiting from the multiple interactions between SO2 and the material offered by anions and hydroxyl groups, iPOP–OH-1 realizes efficient SO2 capture with a high SO2/CO2 selectivity (3948) and a satisfactory SO2 adsorption capacity (1.05 mmol g–1) at 0.002 bar, as well as reversible dynamic separation performance. This work highlights a new design strategy for constructing functional ionic porous polymers toward the efficient separation of low-concentration gases.