ZSM-5 zeolite microparticles(MPs)were synthesized under hydrothermal condition using a low crystal seed addition approach without template.The synthesis parameters such as the seed addition amount,the SiO2/Al2O3ratio,...ZSM-5 zeolite microparticles(MPs)were synthesized under hydrothermal condition using a low crystal seed addition approach without template.The synthesis parameters such as the seed addition amount,the SiO2/Al2O3ratio,the aluminum source,the feeding addition method,aging,and crystallization were investigated.The structure,morphology and composition of the as-synthesized ZSM-5 zeolite MPs were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),laser particle size distribution(PSD)measurements,and inductively coupled plasma-atomic emission spectrometry(ICP-AES).The SiO2/Al2O3ratio of ZSM-5 zeolite MPs was in the range of 20—80.The low seed addition was beneficial to improving the crystallinity and shortening the crystallization time,and the suitable amount of seed was 0.25%(SiO2).The ZSM-5 zeolite MPs synthesized with aluminium nitrate nonahydrate used as the aluminum source exhibited a relatively high crystallinity.An appropriate aging time could eliminate the effect of feeding addition method and effectively adjust particle size.The particle size of ZSM-5 zeolite obtained at an aging time of 20 h was around 2.0μm.Prolonging the aging time appropriately could also shorten the high-temperature crystallization time.The suitable aging time was 24 h,and the relative crystallinity of ZSM-5 zeolite could reach up to 99%after crystallization for 24 h at 180℃.展开更多
基金Financial support from the Innovation Fund for Elitists of Henan Province,China(No.0221001200)the Talent Training Joint Fund of NSFC-Henan(No.U1204203)the China Postdoctoral Science Foundation(No.2012M511121)
文摘ZSM-5 zeolite microparticles(MPs)were synthesized under hydrothermal condition using a low crystal seed addition approach without template.The synthesis parameters such as the seed addition amount,the SiO2/Al2O3ratio,the aluminum source,the feeding addition method,aging,and crystallization were investigated.The structure,morphology and composition of the as-synthesized ZSM-5 zeolite MPs were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),laser particle size distribution(PSD)measurements,and inductively coupled plasma-atomic emission spectrometry(ICP-AES).The SiO2/Al2O3ratio of ZSM-5 zeolite MPs was in the range of 20—80.The low seed addition was beneficial to improving the crystallinity and shortening the crystallization time,and the suitable amount of seed was 0.25%(SiO2).The ZSM-5 zeolite MPs synthesized with aluminium nitrate nonahydrate used as the aluminum source exhibited a relatively high crystallinity.An appropriate aging time could eliminate the effect of feeding addition method and effectively adjust particle size.The particle size of ZSM-5 zeolite obtained at an aging time of 20 h was around 2.0μm.Prolonging the aging time appropriately could also shorten the high-temperature crystallization time.The suitable aging time was 24 h,and the relative crystallinity of ZSM-5 zeolite could reach up to 99%after crystallization for 24 h at 180℃.