Synthesis of ZSM-5 Microspheres Made of Nanocrystals from Iron Ore Tailings by the Solid-Phase Conversion Method

Abstract

ZSM-5 microspheres made of nanocrystals are successfully synthesized from iron ore tailings (IOTs) using a novel and environmentally friendly method, which have a well-defined microporous and mesoporous structure with a large surface area and high acidic strength. In the absence of the liquid water phase during the solidphase conversion, the phase separation between the surfactant and the solid silica phase is able to be bypassed. Compared to conventional methods, such as hydrothermal and steam-assisted conversion methods, this approach enhances the utilization of autoclaves, considerably reduces pollutants, and simplifies the synthetic process, which saves both energy and time. Furthermore, the crystallization of ZSM-5 microspheres via the solid-phase conversion was examined at 413, 433, and 453 K. The results of the kinetic study suggest that the experimental values obtained conform to those of the nonlinear regression model of Kolmogorov−Johnson−Mehl−Avrami for crystallization and nucleation. For the induction, transition, and crystallization stages, the activation energies are 70.96, 39.76, and 36.23 kJ•mol −1 , respectively. The new method is economical and offers a valuable industrially applicable route for the reuse of IOTs to synthesize ZSM-5 microspheres. This synthetic concept could also be expanded to obtain other types of mesoporous zeolites.

Realizing of ZSM-5 microspheres with enhanced catalytic properties prepared from iron ore tailings via solid-phase conversion method

“…Such a trend may be a result of the increase in the dissolution rate of Si and Al in raw materials with the increase in the alkalinity of the precursor, which prevents the participation of these dissolved Si and Al in the crystallization reaction, and therefore these elements remain in the solvent. This reason can also provide a good explanation for the higher yield of silicon and aluminum in the solventfree method than that in the hydrothermal method (Zhang et al, 2020). The SEM results of MP-ZSM-5 synthesized under different pH values (Fig.…”

“…Here, we have successfully synthesized ZSM-5 microspheres based on a solid-phase conversion method from IOT as reported in our previous work (Zhang et al, 2020). The in uence of CTAB/SiO 2 molar ratio and the crystallization process and mechanism are reported and discussed in detail.…”

Carbon Nanotubes/Polydopamine/ZSM-5 Composite Soil Conditioner with Good Controlled Release and Adsorption Properties

“…In addition, zeolite has the characteristics of nontoxicity and good biocompatibility, which can be used for biomedical applications. However, the micropore structure of ZSM-5 restricted the diffusion of macromolecules into and out of micropores, and its drug-carrying properties may not be sufficient for long-term plant growth. − To overcome these problems, the preparation of an efficient and structurally suitable ZSM-5 composite is an important innovation of zeolite in soil pollution applications.…”