Template-Free Synthesis and Catalytic Applications of Microporous and Hierarchical ZSM-5 Zeolites from Natural Aluminosilicate Minerals

Organic templates play a crucial role in zeolite synthesis, but their use causes serious pollutant emissions and increases product costs. Herein, we report a template-free approach to synthesize both microporous and hierarchical ZSM-5 zeolites from natural aluminosilicate mineral, which is achieved by (1) utilizing the mother liquid to construct mesopores without using any mesoscale template and (2) reusing the Si-rich alkali liquor and ion-exchanging solution to improve the atom economy without any alkali/acid liquor discharges. The results show that the resultant zeolites own more open pore channels and less strong acid sites compared with a conventional ZSM-5 zeolite and demonstrate superior catalytic activity in n-octene hydroisomerization. Significantly, compared with the traditional synthesis process, our approach can greatly reduce the material and energy consumptions and pollutant discharges while significantly increase the raw material utilization efficiency, endowing itself as an economic, eco-sustainable, and industrially feasible process.