论文部分内容阅读
建立了通过X-射线衍射(XRD)分析Y沸石骨架硅铝比和结晶度的方法。该方法采用Si粉作为内标物质,通过XRD慢扫描和建立标准曲线法来完成,并对结果的准确性、可靠性和误差进行了讨论,结果显示该方法准确性高,误差小。同时利用建立的实验方法对碱处理不同时间的Y沸石骨架硅铝比和结晶度进行了分析,探讨了碱处理对Y沸石结构影响的原因。发现pH合适的碱处理会导致高硅Y沸石的结晶度先降低后升高,其结构的破坏和重构存在动态平衡,并且骨架Si/Al比从13.1降为2.8,最终高硅Y沸石(DY-0)转化为热力学稳定的常规Y沸石。
A method for the determination of silica to alumina ratio and crystallinity of Y zeolite framework by X-ray diffraction (XRD) was established. The method uses Si powder as the internal standard substance, and is completed by XRD slow scan and standard curve method. The accuracy, reliability and error of the results are discussed. The results show that the method has high accuracy and small error. At the same time, the ratio of silica to alumina and the crystallinity of Y zeolites were analyzed by using the established experimental method at different times. The reason of the effect of alkali treatment on the structure of Y zeolites was also discussed. It was found that the proper alkali treatment resulted in the decrease of the crystallinity of the high-silica Y zeolites and the increase of their crystallinity. The structural failure and reconstruction were dynamically balanced and the Si / Al ratio of the framework was reduced from 13.1 to 2.8. The final high-silica Y zeolite DY-0) to a thermodynamically stable conventional Y zeolite.