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

Key Laboratory of New Low-carbon Green Chemical Technology, Education Department of Guangxi Zhuang Autonomous Region, State Key Laboratory of Featured Metal Materials and Lifecycle Safety for Composite Structures, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China

^* Corresponding author: zhaozhenxia@gxu.edu.cn

Abstract

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.