Chemical Research in Chinese Universities ›› 2024, Vol. 40 ›› Issue (6): 1151-1159.doi: 10.1007/s40242-024-4045-1

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Organic-free, Ultrafast Synthesis of K-CHA Nano-aggregates with Various Morphologies and Their Adsorption Performances

CHU Kailiang1,2, WANG Yaquan1,2, LIU Wenrong1,2, BU Lingzhen1,2, HUANG Yitong1,2, GUO Niandong1,2, QU Liping1,2, SANG Juncai1,2, LI Yaoning1,2, SU Xuemei1,2, ZHANG Xian1,2   

  1. 1. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P. R. China;
    2. Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, P. R. China
  • Received:2024-02-27 Online:2024-12-01 Published:2024-10-26
  • Contact: WANG Yaquan,yqwang@tju.edu.cn E-mail:yqwang@tju.edu.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (No. 21276183).

Abstract: K-Chabazite (K-CHA) zeolites were synthesized with an ultrafast procedure through an eco-friendly and cost-effective “one-pot” method. By solely employing colloidal silica and aluminum hydroxide in the K+/Sr2+ system without the assistance of seeds, fluorides or organic structure as directing agents, the K-CHA nano-aggregates were successfully synthesized in a few hours. The crystallization behavior of the gels with different SiO2/Al2O3 molar ratios (SARs) was investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray fluorescence (XRF), 27Al and 29Si magic angle spinning nuclear magnetic resonance (MAS NMR), Fourier-transform infrared spectra (FTIR), UV-Raman characterizations. As the nucleation rates were changed with the SARs, three kinds of K-CHA nano-aggregates, namely, hamburger-, disk- and walnut-shaped, were obtained. A possible formation mechanism of the K-CHA nano-aggregates was proposed. Additionally, the walnut-shaped sample with an SAR of 7 possessed the largest pore volume and specific surface area, resulting in the highest methane adsorption capacity. Furthermore, it exhibited a CH4/N2 selectivity of more than 3 under relative pressures ranging from 0 to 0.6. This work offers guidance for modifying the stacking modes of other nano-sized zeolites.

Key words: Chabazite, Organic structure directing agent (OSDA)-free, Nano-aggregate, Methane, Adsorption separation