SCI和EI收录∣中国化工学会会刊

›› 2017, Vol. 25 ›› Issue (9): 1303-1313.DOI: 10.1016/j.cjche.2016.11.004

• Energy, Resources and Environmental Technology • 上一篇    下一篇

Synthesis of ZSM-5 with the silica source from industrial hexafluorosilicic acid as transalkylation catalyst

Fang Jin1, Xianqiao Wang1, Tieliang Liu1, Linbo Xiao1,2, Ming Yuan1, Yangchun Fan1   

  1. 1 Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Novel Reactor & Green Chemical Technology Key Laboratory, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073, China;
    2 Hubei SanNing Chemical Industry Joint Stock Co., Ltd, China
  • 收稿日期:2016-09-13 修回日期:2016-11-22 出版日期:2017-09-28 发布日期:2017-10-11
  • 通讯作者: Fang Jin,E-mail:fangjin@wit.edu.cn
  • 基金资助:
    Supported by the National Natural Science Foundation of China (21306143) and the Educational Commission of Hubei Province of China (D20161503) and the Hubei Province Phosphorus Resource and Ethylene Project Downstream Exploitation Collaborative Innovation Center.

Synthesis of ZSM-5 with the silica source from industrial hexafluorosilicic acid as transalkylation catalyst

Fang Jin1, Xianqiao Wang1, Tieliang Liu1, Linbo Xiao1,2, Ming Yuan1, Yangchun Fan1   

  1. 1 Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Novel Reactor & Green Chemical Technology Key Laboratory, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073, China;
    2 Hubei SanNing Chemical Industry Joint Stock Co., Ltd, China
  • Received:2016-09-13 Revised:2016-11-22 Online:2017-09-28 Published:2017-10-11
  • Supported by:
    Supported by the National Natural Science Foundation of China (21306143) and the Educational Commission of Hubei Province of China (D20161503) and the Hubei Province Phosphorus Resource and Ethylene Project Downstream Exploitation Collaborative Innovation Center.

摘要: A new effective process to improve the utilization of industrial fluorosilicic acid of phosphate fertilizer by-product has been investigated to comprehensive application of the silicon and fluorine source. Two-step ammoniation was applied to recover high-quality silica. The recovered silica can be used to hydrothermal synthesize ZSM-5 zeolite without impurity phase contamination, which was confirmed by XRD, TG, SEM, BET and EDS characteristic techniques. It was found that with the increase of SiO2/Al2O3 ratio and the extension of reaction time, the crystal type transform from the orthorhombic to the monoclinic phase. The impurity fluorine content of the recovered SiO2 from H2SiF6 has great influence on the hydrothermal process for ZSM-5 crystal structure formation. Moreover, the increase of fluorine ions content in the hydrothermal process can control the crystal morphology and size of synthesized ZSM-5. Catalytic properties of synthesized HZSM-5 with different SiO2/Al2O3 ratio in transalkylation of toluene and 1,2,4-trimethylbenzene show good and stable catalytic performance. The ZSM-5 synthesized with recovered silica source exhibits similar catalyst life as the performance of small particle size HZSM-5, because the ZSM-5 synthesized with the silica source from industrial hexafluorosilicic acid prefers a thin disk crystal along the b axis direction, which shortens the diffusion distance of generated products.

关键词: Hexafluorosilicic acid, Silica, Hydrothermal synthesis, ZSM-5 zeolite, Transalkylation

Abstract: A new effective process to improve the utilization of industrial fluorosilicic acid of phosphate fertilizer by-product has been investigated to comprehensive application of the silicon and fluorine source. Two-step ammoniation was applied to recover high-quality silica. The recovered silica can be used to hydrothermal synthesize ZSM-5 zeolite without impurity phase contamination, which was confirmed by XRD, TG, SEM, BET and EDS characteristic techniques. It was found that with the increase of SiO2/Al2O3 ratio and the extension of reaction time, the crystal type transform from the orthorhombic to the monoclinic phase. The impurity fluorine content of the recovered SiO2 from H2SiF6 has great influence on the hydrothermal process for ZSM-5 crystal structure formation. Moreover, the increase of fluorine ions content in the hydrothermal process can control the crystal morphology and size of synthesized ZSM-5. Catalytic properties of synthesized HZSM-5 with different SiO2/Al2O3 ratio in transalkylation of toluene and 1,2,4-trimethylbenzene show good and stable catalytic performance. The ZSM-5 synthesized with recovered silica source exhibits similar catalyst life as the performance of small particle size HZSM-5, because the ZSM-5 synthesized with the silica source from industrial hexafluorosilicic acid prefers a thin disk crystal along the b axis direction, which shortens the diffusion distance of generated products.

Key words: Hexafluorosilicic acid, Silica, Hydrothermal synthesis, ZSM-5 zeolite, Transalkylation