Modification and functionalization of zeolites to improve the efficiency of CO2 adsorption: A review

The urgent need to combat climate change by reducing atmospheric carbon dioxide (CO2) levels is emphasized due to its detrimental effects. An extensively employed approach for CO2 removal involves the use of solid adsorbents. Zeolite-based adsorbents, known for their unique structural features, have gained attention for effectively capturing CO2, especially at lower temperatures. However, to optimize CO2 adsorption, modification techniques are crucial. This review explores recent advances in zeolite modification methodologies and their profound impact on CO2 adsorption capacity. It investigates changes in zeolite properties after modification, delves into adsorption thermodynamics and kinetics, and examines the outcomes of these modifications. The surface area, pore size, and the functional groups of modified zeolites create additional CO2 interaction to enhance its adsorption. Among various modification techniques, amine functionalization of zeolites has been widely used for the highest CO2 adsorption capacity. Ion exchange is a technique that enhances CO2 adsorption in flue gases, as it exhibits better selectivity towards CO2 than N2. Furthermore, this review discusses various techniques for modifying zeolites to achieve optimal CO2 adsorption. It also clarifies both the advantages and drawbacks of these methods.