Synthesis of GME zeolite with high porosity by hydrothermal conversion of FAU zeolite using a dual-template method with tetraethylphosphonium and N,N-dimethyl-3,5-dimethylpiepridinium hydroxides

Abstract

Highly crystalline gmelinite (GME) zeolites with Si/Al ratio of ~ 3 were successfully synthesized from FAU zeolites as the starting silica/alumina source using the dual-template method with a mixture of tetraethylphosphonium and N,N-dimethyl-3,5-dimethylpiepridinium cations as an organic structure-directing agent (OSDA). It was also found that the prepared GME zeolite exhibited high porosity when the as-made GME zeolite was K+ ion-exchanged and then calcined at 580 °C at 6 h to remove OSDAs in the zeolitic pores.