Effect of temperature and time in the hydrothermal treatment of HY zeolite
Effect of temperature and time in the hydrothermal treatment of HY zeolite
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DOI：
10.1016/j.micromeso.2005.09.032
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发表时间：
2006-03-20
影响因子：
5.2
通讯作者：
Stöcker, M
中科院分区：
文献类型：
--
作者：
Salman, N;Rüscher, CH;Stöcker, M
将HY沸石在1巴水压下以100 K的步骤从473 K至1073 K汽蒸，该步骤依赖于时间（0.5-20 h）。水热反应可以概括为三条路线：在低温（473 K）下，部分骨架溶解伴随着X射线非晶材料的形成。在中间温度（773-873 K），框架脱铝发生与不同的非框架物种的出现。因此，随着汽蒸时间的增加，Si/Al比的饱和发生在低水平（Si/Al比分别为约4和5）。在973 K时，观察到从低水平的Si/Al饱和度（6）向较高值（11）的交叉，这伴随着沸石的部分非晶化，形成氧化铝和硅胶，并且晶体尺寸也显著减小。在高温（1073 K）下，发生快速热分解。IR光谱直接显示铝硅酸盐相作为骨架的分解产物。在573 K时，沸石骨架保持不变。(c)2005年爱思唯尔公司All rights reserved.
Zeolite HY was steamed at 1 bar water pressure in steps of 100 K from 473 K to 1073 K in dependence of the time (0.5-20 h). Three routes of hydrothermal reactions can be outlined: At low temperature (473 K), a partly framework dissolution occurs accompanied by the formation of X-ray amorphous material. At intermediate temperatures (773-873 K), framework dealumination takes place with the occurrence of different non-framework species. Thereby, with increasing steaming time, saturation of the Si/Al ratio occurs oil low levels (Si/Al ratios of about 4 and 5, respectively). At 973 K, a crossover from a low level saturation in Si/Al (6) towards higher values (11) is observed, which is accompanied by a partial amorphization of the zeolite with formation of aluminium oxide and silica gel and a significant decrease in crystal size as well. At high temperatures (1073 K), a fast thermal decomposition occurs. The IR spectra directly reveal an aluminosilicate phase as decomposition product of the framework. At 573 K, the zeolite framework remains unchanged. (c) 2005 Elsevier Inc. All rights reserved.