CO₂ adsorption by conventional and nanosized zeolites

The applicability of zeolites in controlling the emission of greenhouse gases (GHGs) like carbon dioxide, the most significant GHG, is investigated herein. The structure and properties of conventional and nanosized zeolites are initially introduced; subsequently, the adsorption capacities and selectivities of various types of zeolites are reviewed. Thereafter, the effects of determining factors such as the silica-to-alumina ratio, type of cation, temperature, and pressure are discussed. The zeolites that are beneficial for the storage and/or separation of carbon dioxide are introduced and compared. The analysis results reveal that types X, Y, and A zeolites are beneficial for both the storage and separation of carbon dioxide. Chabazite, which is a natural zeolite, exhibits high potential for the separation of carbon dioxide from methane-rich gaseous streams, such as natural gas and landfill gas. Type ZK-5 is also highly successful in the separation of carbon dioxide from nitrogen-rich streams, such as flue gas. Further investigation of nanosized zeolites revealed that both adsorption capacity and selectivity could be enhanced by reducing the size of zeolites through the synthesis method and further modification via amines impregnation and ion exchange.