Siliceous nanosphere material for CO 2 capture: Kinetics, isotherm, and multicyclic performance studies

Abstract In this work, novel, fibrous‐shaped siliceous nanosphere KAUST Catalysis Center‐1 (KCC‐1) material is synthesized, characterized, and functionalized using different weight percentages of polyethyleneamine for post‐combustion carbon dioxide (CO 2 ) capture. To study the structural properties, various characterization methods, such as field‐emission scanning electron microscopy (FE‐SEM), high‐resolution transmission electron microscopy (HR‐TEM), nitrogen adsorption/desorption isotherms, and powder X‐ray diffraction (PXRD), are used. Morphological studies reveal the fibrous structure of the synthesized KCC‐1 with an average pore size of 3.50 nm and a high specific surface area of 561.13 m 2 /g. The CO 2 capture capacity experiments are investigated using the thermogravimetric method. With an optimized amine loading of 60 wt.% and an adsorption temperature of 75°C, the equilibrium CO 2 uptake capacity is 2.90 mmol CO 2 /g. From the 27 consecutive temperature swing adsorption/regeneration cycles, it is found that the working CO 2 capacity of the sorbent decreases marginally (only 4.80%) and remains nearly stable at about 2.59 mmol CO 2 /g. Finally, the kinetic and isothermal modelling suggest that the kinetics of CO 2 capture is best described by the pseudo‐fractional order model with a deviation of less than 3.62% from experimental data when the adsorption temperature is 75°C, while the modified Toth model is found to best fit the isotherm data with a deviation of less than 2.76% from experimental findings.