模板剂用量对微波水热法制备ZSM-5分子筛的影响研究

Effect of Template Dosages on ZSM-5 Molecular Sieve Fabricated via Microwave Hydrothermal Method

以四丙基氢氧化铵(TPAOH)为模板剂,采用微波水热法制备ZSM-5分子筛。考察模板剂用量对微波水热法合成ZSM-5分子筛物化性质的影响,采用XRD、BET、SEM、NH3-TPD等手段对合成样品的微观结构、孔结构及表面化学性质进行分析表征,在MTO工艺中评价合成分子筛的催化性能。结果表明:模板剂用量对合成ZSM-5分子筛晶相组成、微观形貌、比表面积、孔径分布及表面酸性质具有较大的影响。改变模板剂用量会影响分子筛结晶度和孔结构,可通过模板剂用量调控制备不同酸性质ZSM-5分子筛。模板剂用量为n(TPAOH)∶n(Si O2)=0.35时,ZSM-5分子筛孔结构和表面酸性适中,形貌规整,MTO催化性能最佳,甲醇转化率为98.4%,低碳烯烃收率为75.39%。

The ZSM-5 zeolite was synthesized via microwave hydrothermal method employing tetrapropylammonium hydroxide（ TPAOH） as a template. The effects of the template dosages on physical and chemical properties of ZSM-5 zeolite were investigated in details. The microstructure,pore structure and the surface chemical properties of the crystals were characterized by XRD,BET,SEM and NH3-TPD,and the catalytic performance of ZSM-5zeolite was studied on MTO reaction. The results indicate that the template dosages had a great influence on the phase composition,morphology,specific surface area,pore size distribution and the surface chemical properties of the synthesized products. The Changes of the template dosages will affect the crystallinty and pore structure of molecular sieve,and ZSM-5 with different acid properties can also be prepared by controlling template dosages.The template dosage of n（ TPAOH） ∶ n（ Si O2） = 0. 35,ZSM-5 zeolite had appropriate structure properties,and the methanol conversion and the yield of olefins were of 98. 4% and 75. 39% respectively.