Studies of the effect of synthesis parameters on ZSM-5 nanocrystalline material during template-hydrothermal synthesis in the presence of chelating agent

Nanostructure ZSM-5 zeolite was synthesised via hydrothermal, chelating agent-based method from a mixture with molar composition of 1Al2O3:46SiO2:xTPA:5Na2O:1.3Trien:2500H2O (x = 0–5.5). The effects of crystallisation time and temperature and template type and content on the synthesised zeolite crystallinity and morphology were investigated. The final products were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Both XRD and SEM results showed that the crystallinity and particle size of the synthesised zeolite increase with increasing crystallisation time for both templates. However, twinned and intergrown crystals of ZSM-5 zeolite with very smooth surfaces were obtained with a crystallisation time of 120 h using a tetrapropylammonium hydroxide (TPAOH) template. Also, the crystallisation temperature had a strong effect on crystallinity and morphology; a highly crystalline ZSM-5 zeolite with twinned crystals was synthesised at 175 °C. Furthermore, the template content had a strong effect on the final product properties. ZSM-5 zeolite with high crystallinity and perfect particles was synthesised at a TPAOH/Si ratio of 0.058. Finally, the effect of the chelating agent (Trien) on crystallinity and morphology of the synthesised ZSM-5 was investigated.