Growth Study of Hierarchical Pore SSZ-13 Molecular Sieves with Improved CO2 Adsorption Performance

Abstract

SSZ-13, with a unique pore structure and excellent thermal stability, showed a potential application in the adsorption and catalysis industry. In this work, Al(NO3)3 was used as an Al source to study the performance and morphology of the zeolite. The zeolite was prepared with an unconventional process by adding an Al source before the structure-directing agent and base. When inorganic oxygen-containing anions were introduced into the unconventional synthesis system, the crystals of the zeolite conform to the unconventional growth mode. The zeolites with large crystals were assembled from small unit nanocrystals. Extending the reaction time, aging time and adding fluoride ions introduced a multistage pore structure on the surface of the molecular sieve, which improved the CO2 adsorption performance. When aging for 24 h, reaction for 96 h, and the amount of fluorine added was 0.05 (F/Si), the sample had the best hierarchical pore structure. The SSZ-13 molecular sieve with an added amount of 0.1 (F/Si) has the highest CO2 adsorption performance. The adsorption amount was 4.55 mmol/g at 1 bar, which is 20.4% higher than that of zeolite SSZ-13 prepared by the conventional process.

Recent Advances in Post-Combustion CO2 Capture via Adsorption Methods

“…Runlin Han et al prepared SSZ-13 via an unconventional process by adding Al(NO3)3 as the aluminum resource before the structure-directing agent and base. In this case, SSZ-13 was crystallized by an unconventional growth mechanism [30]. Based on the preparation of SSZ-13, the author also optimized the effects of aging time and the number of fluoride ions on the adsorption effect.…”

Nitrogen- and Halogen-Free Multifunctional Polymer-Directed Fabrication of Aluminum-Rich Hierarchical MFI Zeolites

“…Furthermore, apart from acidity, accessibility to acid sites is also crucial for the conventional microporous Al-rich ZSM-5 zeolite that suffers from diffusion limitation leading to rapid deactivation in the practical applications because of coke deposition. However, the accessibility to acid sites can be improved by creating mesopores in the microporous zeolites [ 13 , 14 , 15 , 16 ]. Post-synthetic desilication of Al-rich ZSM-5 zeolites (Si/Al ratio < 25) to generate additional mesopores is relatively unexploited because the high Al concentration in the framework hinders the extraction of silicon from the zeolite structure [ 17 ].…”