Functional ionic liquid anchored TS-1 molecular sieve with multiple adsorption sites for efficient capture and separation of CO2 in flue gas systems

Abstract

Solid adsorption using porous molecular sieves are promising technology to capture CO2 from the air and industrial gases. However, the adsorption capacity and stability for most molecular sieves in complex gas systems are undesirable. The presence of alkaline substances can improve the absorption capacity of materials by altering the surface properties and enhancing the interaction with CO2. To improve the adsorption performance, we introduced amine functionalized ionic liquids (ILs) 1-aminopropyl-3-methylimidazolium bromide (APMImBr, with one amine group) and Bis-(3-aminopropyl-1-imidazole) ethylidene dibromide (BAPImEDB, with two amine group) on the surface of TS-1 molecular sieve. Under optimal experimental conditions, APMImBr and BAPImEDB modified TS-1 molecular sieves have high adsorption capacity (increased by 148.5% and 218%, respectively) and universal adaptability and renewability. According to CO2-TPD, XPS spectrum and quantum chemical calculations, the role of amine-based ILs can significantly enhance the weak and medium-strength basic sites, forming a multi-point alkaline effect and enhancing the adsorption capacity through weak interactions (van der waals and hydrogen bonding) with CO2. Overall, the research on multi amine functionalized ionic liquid composite solid adsorbents based on porous molecular sieves for carbon dioxide capture and recovery provides valuable insights for achieving sustainable development goals.