高稳定性纳米Y分子筛的合成和表征OA

Nano-sized Y zeolite has attracted increasing attention in the petroleum refining industry due to its excellent diffusion properties and abundant external surface acid sites.However,synthesizing highly stable nanosized Y zeolite still remains challenging.A novel hydrothermal crystallization method was developed using inexpensive anionic surfactant ammonium fatty alcohol ether sulfate(AESA)as a template agent.The synthesis involved a strategy of multiple gel formation steps,multi-stage crystallization,and post-addition of silicon source.The effects of synthesis conditions,AESA/Al2O3 ratio,and Na2O/Al2O3 ratio on the morphology and physicochemical properties of the zeolite were investigated.The synthesized materials were characterized by powder X-ray diffraction(XRD),X-ray fluorescence spectroscopy(XRF),N2 physisorption fourier transform infrared spectroscopy(FT-IR),pyridine-adsorbed FT-IR(Py-FTIR),solid-state NMR(29Si MAS NMR and 27Al MAS NMR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and EDS-mapping.The hydrothermal stability at high temperatures was compared between the nano-sized Y and commercial Y zeolites.The results demonstrate that under optimized synthesis conditions,the nano-sized zeolite exhibits an average particle size of 83 nm,a silica-alumina ratio(SAR)of 5.8,a unit cell parameter of 24.62 Å,and a specific surface area of 887 m2/g.After hydrothermal treatment at 600℃,the reduction rate of relative crystallinity was 16.0％,which recovered to 7.1％after acid treatment.Compared to commercial Y zeolite,the nano-sized Y zeolite possesses highly developed secondary pore structure(pore size distribution mainly in the 10～80 nm range),retains more acid sites,and exhibits superior stability,which were attributed to its improved framework integrity and higher SAR.