Novel amino-functionalized poly(ionic liquid)s for enhanced acetaldehyde adsorption: synthesis and performance evaluation

Abstract

The excellent adsorption potential of poly(ionic liquid)s was utilized in amino-functionalized poly(ionic liquid) (PVABn) materials constructed for the efficient adsorption of volatile organic compounds (VOCs). 1-Vinyl-3-(3-aminopropyl)-imidazolium bromide was synthesized via a quaternization reaction using 1-vinylimidazole and 3-bromopropylamine hydrobromide as raw materials. Four PVABn adsorbents (PVABn-2, PVABn-3, PVABn-4, and PVABn-5) with micro–mesoporous structures were prepared by polymerization with various concentrations of the divinylbenzene cross-linker (molar ratios 2 : 5, 3 : 5, 4 : 5, and 5 : 5, respectively). Preliminary static adsorption experiments with PVABn-x were conducted for five volatile organic compounds (VOCs): chloroform, toluene, diethyl ether, acetone, and acetaldehyde. The results demonstrated that PVABn-x exhibited significantly higher adsorption capacity for acetaldehyde than for the other VOCs and the materials hosted many chemically active sites, which provided substantial adsorption capacity for acetaldehyde gas. PVABn-4 exhibited the greatest capacity of 310.8 mg g⁻¹, thus overcoming the limitation of insufficient specific surface area. Kinetic and isotherm studies showed that adsorption conformed to the Bangham kinetic model and the Freundlich isotherm model, indicating that it was mainly driven by physical processes. Cyclic adsorption on PVABn-4 was investigated using high-temperature nitrogen purge desorption. After five adsorption–desorption cycles, adsorption decreased to 288.9 mg g⁻¹, which is >90% of the initial value and therefore indicates excellent stability and renewability. This work offers an effective design strategy for high-performance, reusable PIL-based adsorbents, with great promise for VOC capture and environmental remediation.