Seed-Assisted, OSDA-Free, Solvent-Free Synthesis of ZSM-5 Zeolite from Iron Ore Tailings

Abstract

Comprehensive utilization of iron ore tailings (IOT) not only solves environmental problems but also creates huge economic benefits. Our approach is focused on reutilization of IOT by converting it to ZSM-5 zeolite. The solvent and organic structure-directing agents (OSDA) used in the hydrothermal synthesis of ZSM-5 zeolite are major obstacles to achieve the sustainable synthesis routes. Therefore, the development of environmentally friendly ZSM-5 zeolite synthesis method is strongly desired. Here, ZSM-5 zeolite is synthesized successfully from IOT via a seed-assisted, solvent-free method without using the organic template or solvent. In addition, the influences of Na2CO3·10H2O/SiO2 molar ratio, amount of seeds, and crystallization process of ZSM-5 are systematically investigated. The raw materials and as-synthesized products are characterized by XRD, XRF, SEM, 27Al MAS NMR, and BET analysis; and the ZSM-5 zeolite synthesized by seed-assisted, OSDA-free, solvent-free method has the same mesoporous and microporous structure as the seed crystal. The synthetic route proposed in this work provides a novel green alternative for the synthesis of ZSM-5 from IOT. Figure schematic illustration of the seed-assisted, OSDA-free, solvent-free synthesis of ZSM-5 .