Insights to Achieve a Better Control of Silicon-Aluminum Ratio and ZSM-5 Zeolite Crystal Morphology through the Assistance of Biomass

Alessandra Silva,Leandro Miranda,Benoit Louis,Marcelo Pereira,Márcio Nele

doi:10.3390/catal6020030

Alessandra Silva, Leandro Miranda + Show 3 more

Open Access

https://doi.org/10.3390/catal6020030

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Abstract

The present study attempts to provide insights for both the chemical composition (Si/Al) and the crystal morphology of ZSM-5 zeolites while using biomass template compounds in the synthesis. The solution containing biomass-derivative compounds was obtained after treating biomass in a sodium hydroxide aqueous solution under reflux. The latter alkaline solution was used as a solvent for zeolite nuclei ingredients to form the gel phase under hydrothermal conditions (170 °C during 24, 48 or 72 h). This approach allowed for preparing MFI zeolites having a broad range of Si/Al ratio, i.e., from 25 to 150. Likewise, MFI crystals with different morphologies could be obtained, being different from the pristine zeolite formed in the absence of biomass.

Highlights

ZSM-5 zeolite, discovered by Mobil Company, is a member of commonly called “big five” zeolites and has been used in several acid-catalyzed processes
No improvement in alumina textural properties prepared in the presence of a solution containing biomass-extracted compounds could be observed. These results suggest that biomass or biomass-derived components formed under in-situ synthesis conditions induce changes in the self-assembly process
In order to investigate whether the alkaline hydrolyzate from sugar-cane bagasse has an influence on the chemical composition or crystal size/morphology of ZSM-5 zeolite when added as a co-component in its synthesis, we performed the following steps: i ii iii

Summary

Introduction

ZSM-5 zeolite, discovered by Mobil Company, is a member of commonly called “big five” zeolites and has been used in several acid-catalyzed processes. It is important to highlight that small ZSM-5 crystals increased both alkane cracking activity and selectivity toward propylene and ethylene compared with large crystals [14] This simple and inexpensive method was applied to the preparation of γ-alumina and resulted both in surface area and pore volume increases of up to 2.5-fold and 1.5-fold, respectively, when compared to alumina preparation in the absence of biomass [15]. No improvement in alumina textural properties prepared in the presence of a solution containing biomass-extracted compounds could be observed These results suggest that biomass or biomass-derived components formed under in-situ synthesis conditions induce changes (minor or major) in the self-assembly process. The effect of biomass derived-compounds, obtained by prior alkaline sugar-cane bagasse hydrolysis, was evaluated in ZSM-5 zeolite preparations

Results and Discussion

Diffraction patterns the different zeolites: seriesforand

Experimental Section

Conclusions