Abstract

HZSM-5 zeolite modified by rare earth was prepared with ion exchange method in the study. The effects of different types of rare earth elements, modification temperatures, pH, and rare earth contents on structural stability of the as-prepared zeolite were investigated. The as-prepared zeolite was characterized by XRD, SEM and FT-IR spectroscopy. The characterization results showed that the crystal structure of the zeolite was not changed by the modification of rare earth, which was evenly distributed on the surface or in the pore channel of zeolite. Sm/HZSM-5 zeolite with the highest structural stability was obtained under the following modification conditions: 2% rare earth Sm, modification temperature of 70 °C, 2 h of ion exchange, and pH 3.

摘要

本研究采用离子交换法制备稀土改性HZSM-5沸石。研究了不同稀土元素种类、改性温度、pH值和稀土含量对所制备沸石结构稳定性的影响。所制备的沸石通过XRD、SEM和FT-IR光谱进行表征。表征结果表明，稀土的改性并未改变沸石的晶体结构，稀土均匀分布在沸石表面或孔道中。在以下改性条件下获得了结构稳定性最高的Sm/HZSM-5分子筛：2%稀土Sm，改性温度70 ℃，离子交换2 h，pH 3。