التفاصيل البيبلوغرافية
| العنوان: |
Effect of temperature and time in the hydrothermal treatment of HY zeolite |
| المؤلفون: |
Salman, N.1, Rüscher, C.H.1, Buhl, J.-Chr.1, Lutz, W.2 wolfgang.lutz@tricatgroup.de, Toufar, H.2, Stöcker, M.3 |
| المصدر: |
Microporous & Mesoporous Materials. Mar2006, Vol. 90 Issue 1-3, p339-346. 8p. |
| مصطلحات موضوعية: |
*ZEOLITES, *TEMPERATURE, *ALUMINUM oxide, *SPECTRUM analysis |
| مستخلص: |
Abstract: Zeolite HY was steamed at 1bar water pressure in steps of 100K from 473K to 1073K in dependence of the time (0.5–20h). Three routes of hydrothermal reactions can be outlined: At low temperature (473K), a partly framework dissolution occurs accompanied by the formation of X-ray amorphous material. At intermediate temperatures (773–873K), framework dealumination takes place with the occurrence of different non-framework species. Thereby, with increasing steaming time, saturation of the Si/Al ratio occurs on low levels (Si/Al ratios of about 4 and 5, respectively). At 973K, 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 (1073K), a fast thermal decomposition occurs. The IR spectra directly reveal an aluminosilicate phase as decomposition product of the framework. At 573K, the zeolite framework remains unchanged. [Copyright &y& Elsevier] |
| قاعدة البيانات: |
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