Synthesis of Aggregate ZSM-5 Zeolite with Nucleation Gel in the Absence of Organic Template

The effect of nucleation gel on the preparation of aggregate ZSM-5 zeolite was studied under rotating autoclaves free from the organic structure-directing agent.The influence of the nucleation gel on the crystallization rate and particle size was investigated in detail.The physicochemical properties of the products were characterized by using XRD,SEM,and N2 adsorption.The results indicate that the crystallization rate of the ZSM-5 zeolite is increased by the addition of the nucleation gel.The crystallization time with 33.3wt% nucleation gel is 24 h while that without nucleation gel is 48 h.When 33.3wt% nucleation gel is added,after crystallization at 150 ℃ for 24 h,the average size of the aggregate is increased from 5.5 μm to 26.3 μm,and the specific surface area is increased from 292 m2·g-1 to 394 m2·g-1.The mechanism for the crystal growth of the aggregate zeolite ZSM-5 without organic template by the nucleation gel method is also discussed in this work.