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采用无机铁、硅原料合成不同组成的MFI型硅铁沸石。通过碱酸处理对质子化硅铁沸石进行介孔改性。用X射线衍射、Fourier变换红外光谱、紫外–可见光谱、N_2吸附、扫描电子显微镜和能量色散X射线谱表征沸石的晶体和孔结构性质,探究骨架Si/Fe摩尔比与晶内介孔率和Si、Fe脱除行为的关系。结果表明:合成的硅铁酸盐是结晶性好的Fe~(3+)同构取代MFI型沸石;系列改性硅铁沸石具有较高的结晶度保留率、脱硅选择性、介孔率及二级介孔分布特征。骨架Si/Fe比是影响沸石选择性脱硅和介孔形成的关键因素。起始Si/Fe比为60~120的改性沸石具有更高的介孔率及Si、Fe脱除效率。
Adopting inorganic iron and silicon raw materials to synthesize MFI type ferrosilicon zeolite with different compositions. The protonated ferrosiliconite was mesoporous modified by alkali treatment. The crystal and pore structure properties of zeolite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, UV-Vis spectroscopy, N 2 adsorption, scanning electron microscopy and energy dispersive X-ray spectroscopy. Si, Fe removal behavior of the relationship. The results show that the synthesized ferrosilicate is a kind of Fe 3+ isomorphously substituted MFI zeolite with good crystallinity. The series of modified ferrosilicites have high retention of crystallinity, desilication selectivity, mesoporous rate And secondary mesopores distribution characteristics. Skeletal Si / Fe ratio is a key factor affecting the selective desilication and mesopore formation of zeolites. The modified zeolite with a starting Si / Fe ratio of 60-120 has higher mesoporosity and Si and Fe removal efficiencies.