Optimization of crystal growth of sub-micron ZSM-5 zeolite prepared by using Al(OH)3 extracted from fly ash as an aluminum source

Yanguang Chen; Shuli Cong; Qiqi Wang; Hongjing Han; Jia Lu; Yue Kang; Wei Kang; Haiying Wang; Shuyu Han; Hua Song; Jiaojing Zhang

doi:10.1016/j.jhazmat.2018.01.004

Optimization of crystal growth of sub-micron ZSM-5 zeolite prepared by using Al(OH)₃ extracted from fly ash as an aluminum source

J Hazard Mater. 2018 May 5:349:18-26. doi: 10.1016/j.jhazmat.2018.01.004. Epub 2018 Jan 12.

Authors

Yanguang Chen¹, Shuli Cong², Qiqi Wang², Hongjing Han², Jia Lu³, Yue Kang², Wei Kang², Haiying Wang², Shuyu Han², Hua Song², Jiaojing Zhang²

Affiliations

¹ College of Chemistry & Chemical Engineering, Northeast Petroleum University, Daqing, 163318, China; Provincial Key Laboratory of Oil & Gas Chemical Technology, Northeast Petroleum University, Daqing, 163318, China. Electronic address: ygchen79310@126.com.
² College of Chemistry & Chemical Engineering, Northeast Petroleum University, Daqing, 163318, China; Provincial Key Laboratory of Oil & Gas Chemical Technology, Northeast Petroleum University, Daqing, 163318, China.
³ Energy & Environmental Research Institute of Heilongjiang Province, Harbin, 150027, China.

PMID: 29414748
DOI: 10.1016/j.jhazmat.2018.01.004

Abstract

A novel approach was proposed to prepare ZSM-5 zeolite via hydrothermal synthesis by using Al(OH)₃, which was extracted from fly ash by a staged treatment, as an aluminum source. The synthesis parameters and crystal growth of ZSM-5 were optimized. The optimization of crystal growth for ZSM-5 was investigated under the effect of organic steric-hindrance agents. The crystal phase and morphology of the ZSM-5 were characterized by X-ray diffractometry and scanning electron microscopy, and the particle size distribution was measured by laser particle-size analyzer. The crystal growth of ZSM-5 under different hydrothermal conditions obeyed the "S" regulation. According to the analysis, the formation of ZSM-5 crystal occurred via four steps: (1) the formation of amorphous aluminosilicate by the condensation of silicate ions and aluminate ions; (2) the particle growth and aggregation of the amorphous aluminosilicate; (3) crystallization and crystal growth of ZSM-5; (4) Gentle growth after the zeolite crystal reaches a certain size. The addition of organic steric hindrance agents resulted in a decrease in grain size and crystal-particle formation with a narrow size distribution. Single-grain dispersion resulted and the micropore volume, mesopore volume, and specific surface areas were improved by the presence of organic steric agents.

Keywords: Coal fly ash; Crystallization curve; Regulation of crystal growth; Steric-hindrance agent; ZSM-5 zeolite.