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以天然CXN沸石为基底材料,通过离子交换、焙烧和酸处理等方法研究了影响该沸石水热稳定性的因素.XRD,XRF和27Al MAS NMR等结果表明阳离子种类和位置均会影响沸石水热稳定性,其中铵型CXN沸石的水热稳定性最高.高温焙烧铵型CXN沸石虽能提高骨架硅铝比,但骨架缺陷增多导致其水热稳定性下降.还研究了水蒸汽量、处理温度和时间对沸石骨架结构变化的影响,结果表明提高温度和水蒸汽量均会降低沸石结晶度,但处理时间则对结晶度的影响较小.
The natural CXN zeolite was used as the substrate material to study the factors affecting the hydrothermal stability of the zeolite by ion exchange, calcination and acid treatment.The results of XRD, XRF and 27Al MAS NMR showed that both the cationic species and the position affected the hydrothermal Stability, in which ammonium-type CXN zeolite has the highest hydrothermal stability.The high-temperature calcination of ammonium-type CXN zeolite can improve the ratio of silicon to aluminum, but the increase of the skeleton defects leads to the decrease of the hydrothermal stability.The effects of water vapor amount, treatment temperature And time on the structure of the zeolite framework, the results show that the increase of temperature and water vapor will reduce the zeolite crystallinity, but the processing time has little effect on the crystallinity.