Dual spatial region flexible chlorine based ionic hypercrosslinked polymer synergistically adsorb formaldehyde and carbon dioxide

Efficient adsorption and purification of low concentration volatile organic compounds (VOCs) and carbon dioxide (CO2) mixture in high-humidity environments remain a daunting challenge for researchers. In this study, a dual spatial region synergistic adsorption strategy was proposed to achieve synchronous and efficient capture of formaldehyde and CO2 on flexible chlorine (Cl) based ionic hypercross-linked polymer (Cl-IHCP). Through the ordered self-assembly of ionic monomers, the array-distributed free Cl, terminal Cl, and pyrrole nitrogen (N) sites were integrated into the skeletal network of Cl-IHCP and formed ultra-microporous environment with two different adsorption regions. Different adsorption regions exhibited varying adsorption affinities for formaldehyde and CO2 molecules on three sites, thereby weakening their competitive adsorption and achieving high adsorption for both. Besides, the strong binding force of formaldehyde and CO2 molecules in different regions makes the skeleton-responsive swelling of Cl-IHCP, and created new adsorption microenvironments for the other adsorbate. This manner considerably enhanced the adsorption capacity of Cl-IHCP for formaldehyde and CO2 in mixed-component, increasing by approximately 45% and 70% respectively compared to single component formaldehyde and CO2. These fascinating properties enabled Cl-IHCP to synergistically adsorb formaldehyde and CO2 mixtures in high humidity environments. This study innovatively proposed a simple and cost-effective strategy for removing VOCs and CO2 under high humidity, providing a feasible solution for green air purification technology.