Chemical Journal of Chinese Universities ›› 2020, Vol. 41 ›› Issue (11): 2449-2456.doi: 10.7503/cjcu20200289

• Inorganic Chemistry • Previous Articles     Next Articles

Influence Mechanism of Particle Size and Distribution of Silica Sol in the Synthesis of Ferrierite Zeolite with High SiO2/Al2O3 Ratio

DONG Le, HUANG Xingliang(), REN Junjie, DAI Xiaoping, LIU Zongyan, TIAN Hongfeng, WANG Zhidong, WU Xiaotong   

  1. College of Chemical Engineering and Environment,China University of Petroleum,Beijing 102249,China
  • Received:2020-05-25 Online:2020-11-10 Published:2020-11-06
  • Contact: HUANG Xingliang E-mail:xlhuang@cup.edu.cn
  • Supported by:
    Supported by the National Natural Science Foundation of China(U1662104)

Abstract:

Silica sol mother liquids with different particle sizes and distributions were prepared by pre- treating silica sol in solutions of different alkalinities, and then they were used as silicon source to synthesize high-silica ferrierite(FER) zeolites. Mother liquids and products were characterized by means of laser particle size analyzer(LPSA), Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), scanning electron microscopy/energy dispersive X-ray spectroscopy(SEM-EDS) and X-ray fluorescence(XRF) spectroscopy. The influences of alkalinity on the particle size characteristics of silica sol mother liquid, the crystallization process, and products were investigated. Results indicated that the particle size of the silica sol mother liquid gradually increased with the alkalinity, corresponding to the transition of more Q3 silicon units to Q2 silicon units in the solution. At low alkalinity, Q3 silicon units with a high degree of polymerization tended to make crystallization follow the solid-phase transformation mechanism to synthesize pure phase big ferrierite crystals with high yield and relative crystallinity; while at high alkalinity, a large number of active Q2 silicon units tended to make the gel coagulate with each other, and the crystallization process followed the liquid-phase transformation mechanism, affording small product with low purity and yield.

Key words: FER zeolite, High SiO2/Al2O3 ratio, Hydrothermal synthesis, Silica sol, Particle size and distribution

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