碱溶液刻蚀法制备介孔Y型分子筛及其性能表征

摘要

Mesoporous Y Zeolites were prepared by alkaline solution etching method using industrial NaY zeolite powders as raw materials.The crystal structure of the samples was characterized using X-ray diffraction (XRD)and skeleton Fourier transform infrared spectroscopy (FTIR).The pore structure and morphology were measured by N2 adsorption isotherms and scanning electron microscopy (SEM).The acid properties were characterized using pyridine-infrared spectroscopy (Py-FTIR) technique.The results show that NaY zeolites can maintain the topology of zeolite crystal and basic morphology structure after treated in a suitable concentration by alkaline solution at mild conditions.A defected mesoporous structure in the zeolite is obtained in the process of alkaline solution etching.In addition,the alkali etching has little effect on the amount of B acid sites of H type zeolites,while,the number of L acid centers greatly reduces in the mesoporous Y Zeolites.%采用碱溶液刻蚀法由工业生产的 NaY 分子筛原粉制备介孔 Y 型分子筛。运用 X 射线衍射(XRD)和骨架红外光谱(FTIR)表征样品的晶体结构,N2吸附等温线和扫描电镜(SEM)表征孔结构和形貌特征,并采用吡啶红外光谱技术(Py-FTIR)表征样品的酸性能。结果表明,NaY 分子筛在适当浓度的碱溶液以及较温和的条件下,处理后可保持分子筛晶体的拓扑结构和基本形貌结构,但在处理过程中晶粒表面或晶粒内可被刻蚀出一定的缺陷介孔结构。另外,碱刻蚀前后对改性后 H 型分子筛中 B 酸中心量的影响不明显,但大大减少了 L 酸中心的数量。