Effect of pre-dealumination by (NH4)2SiF6 on the properties of ZSM-5 with steam aging treatment

XRD, 29 Si MAS, NMR, Poisoning-Step-Temperature-Programmed-Depoisoning method (PSTPD) and n-hexadecane cracking are used to study the effect of (NH 4 ) 2 SiF 6 pre-dealumination on the structure, acidity and catalytic performance of producing light-olefins of ZSM-5 which is treated by steam at 800°C for 4h after pre-dealumination.